Hastings' Dictionary of the New Testament 
1. The historic manifestation .—We shall not attempt in this article to say anything about such manifestations of Christ as those alluded to in John 1:9, where He is spoken of as the Light which lighteth every man coming into the world. Our first point must obviously be that manifestation in the flesh of which St. Paul speaks in his letter to Timothy ( 1 Timothy 3:16). We are so accustomed to its outward form that to some extent we have lost its significance. Not in the court as a king’s son, not in the Temple as the member of a priestly family, not in the wilderness as the son of some aged solitary who had given up the world, but in the familiar commonplace surroundings of a peasant family, as the Son of Mary, the wife of a village carpenter. This was the presentation of God to the world. Any of the other forms would have been more in accord with human expectations. But we are learning more and more every day that God loves the natural, not the out-of-the-way, as a means for manifestation. And this manifestation, first in the manger at Bethlehem, then in the home at Nazareth, was the outward setting of the Divine Life, both simple and natural. There were no miracles, no strange exhibitions of unseen powers, no external signs that led the men of Nazareth to mark out that home as being specially remarkable. Mary and Joseph, who alone knew the secret, read the wonder of it in the spotless life which from infancy to manhood unfolded new beauties every day. Nothing like it had they ever seen or heard.
2. Manifestation by signs .—But this manifestation of God in human character, though the only one seen during thirty out of thirty-three years, was not the only one. His mother evidently expected something further. When He left His home to begin His ministry, she felt sure that this reserve and silence would be broken. It might come at any place, and at any time. And it was in accord with the humility and kindness of her character that she should believe it might come at a small village feast to meet a temporary social need. It is plain from our Lord’s reply ( John 2:4) that she was looking for some manifestation, for He told her that the hour for such had not come. It is equally plain that she read in His words only a correction of her eagerness and supposition that she best knew the occasion. She had no doubt that He would help, and gave directions accordingly. And in that secret miracle, apparently unperceived at the time, and discovered only when there was an opportunity to ask the servants, He manifested forth His glory.
This is typical of the many manifestations that followed during the three years. They were not wonders wrought to force men’s belief, but signs of Divine character. They were bits of teaching by illustration, object-lessons as we should call them. He never would work a miracle for the sake of astonishing men, though He was often asked to do so ( Matthew 12:38 ff; Matthew 16:1 ff.). They were all signs of God’s sympathy with the needs of men, and the desire He had to relieve them. (See Wace, Some Central Points of Our Lord’s Ministry , p. 133).
3. Manifestation of the Transfiguration .—For some eighteen months there had been wonderful manifestations of Divine character and power, but no personal manifestation. Like any one else, Christ was seen tired, hungry, asleep, and in pain through the infirmities and sicknesses of others that He carried. He did not strive nor cry, neither was His voice heard in the streets ( Matthew 12:19). All was singularly quiet and unassuming, and men might well wonder what there was at the back of this astonishing teaching and these wonderful works. But once the disclosure was made ( Matthew 17:1 f. || Mark 9:2 f., Luke 9:28 f.). See art. Transfiguration.
4. Manifestations after the Resurrection .—It is very difficult to realize the character of these revelations of the Risen Lord. In one He is like a gardener ( John 20:15), in another, a traveller walking to a country village ( Luke 24:15), in another, a stranger standing on the beach of the Lake ( John 21:4). Mk. speaks of the appearance to the two disciples on the road to Emmaus as being in ‘another form’ ( Mark 16:12). They were manifestations marked by sudden appearances and disappearances. His home was elsewhere, but He came and went according to the disciples’ needs. The body was real—could be touched as well as seen. Indeed, He was anxious that they should not suppose Him to be mere spirit, and actually ate a piece of broiled fish before them in order to show them the reality of His bodily existence ( Luke 24:42). But these manifestations are characterized by two features: (1) they were made only to His friends; (2) they were not apparently surrounded with glory and majesty.
With regard to (1), we may believe that only His friends could have perceived them. They might have seen something , as St. Paul’s companions did on the road to Damascus ( Acts 9:7), but not the face of Christ. Faith and love were necessary to interpret the manifestations. (2) They were not apparently surrounded with glory and majesty. They disturbed and frightened, not because they were expressions of His eternal majesty, as that of the Transfiguration was, but because they were unexpected and sudden. This, we think, is singular, and certainly one of the marks of the truthfulness of the narrative. We expect it to be so different, as is shown by the shining figures that represent the Risen Lord in picture and stained-glass window. But just as the graciousness of a king leads him to adopt the dress of his guest so as to make him more completely at home, so our King, when He comes to those poor labouring folk whom He had chosen for His Apostles, comes as one of them.
5. Manifestations to disciples since the Ascension .—There is a striking promise in the words our Lord spoke after the Last Supper, in which He declares that He will manifest Himself to the man that loves Him. That this does not refer to the manifestations of the Resurrection, which were so soon to follow, is clear from His reply to Jude’s very natural question as to how He would manifest Himself to the disciples and yet not to the world ( John 14:22). It is interesting, to note that St. John does not use the ordinary Greek word (φανερόω) for manifestation, but takes another word (ἐμφανίζω), which is employed in this sense in only one other passage ( Matthew 27:53), where the dead bodies of the saints are said to have appeared to many in the holy city. That passage would seem to indicate a bodily appearance; but our Lord’s explanation contradicts such an interpretation. When asked how He could appear to the men who loved Him and yet not to the world, He replies that in the first place the man who loves Him will keep His word, i.e. will give his mind to Him, and observe His teaching, and then in his fixed contemplation and obedience will realize not only His own presence, but the presence of the Father. Such manifestations as these, then, are secret, personal realizations of Christ’s presence, according more nearly with the revelations of a friend’s character that we have in his letters, or in his pictures if he is an artist, in his music if he is a musician. Not, however, that we are to think of them as entirely, subjective. The words ‘We will come unto him’ teach an actual spiritual movement on our Lord’s part towards those who love Him, which they will feel and enjoy.
To St. Paul, who did enjoy some actual appearances of Christ, the spiritual revelations were everything; and in one difficult passage he declares that though he had known Christ after the flesh, i.e. in bodily form, henceforth he knew Him no longer in that way ( 2 Corinthians 5:16), evidently finding more in the indwelling manifestation of Christ than he had known in the joy of Christ’s visible form.
6. Manifestation of the Second Advent .—In 2 Thessalonians 2:8, where Authorized Version gives ‘with the brightness of his coming,’ Revised Version NT 1881, OT 1885 renders ‘by the manifestation of his coming,’ the Gr. word being ἐπιφάνεια. Similarly Revised Version NT 1881, OT 1885 substitutes ‘shall be manifested’ for Authorized Version ‘shall appear’ in Colossians 3:4, 1 Peter 5:4, 1 John 2:28; 1 John 3:2, the Gr. word in each case being φανερόω. See artt. Parousia, Second Coming.
G. H. S. Walpole.
Vine's Expository Dictionary of NT Words 
"a manifestation" (akin to phaneros and phaneroo; see Manifest occurs in 1—Corinthians 12:7; 2—Corinthians 4:2 .
King James Dictionary 
MANIFESTA'TION, n. The act of disclosing what is secret, unseen or obscure discovery to the eye or to the understanding the exhibition of any thing by clear evidence display as the manifestation of God's power in creation, or of his benevolence in redemption.
The secret manner in which acts of mercy ought to be performed, requires this public manifestation of them at the great day.
Webster's Dictionary 
(n.) The act of manifesting or disclosing, or the state of being manifested; discovery to the eye or to the understanding; also, that which manifests; exhibition; display; revelation; as, the manifestation of God's power in creation.