Vine's Expository Dictionary of NT Words 
"a limb of the body," is used (a) literally, Matthew 5:29,30; Romans 6:13 (twice),19 (twice); 7:5,23 (twice); 12:4 (twice); 1—Corinthians 12:12 (twice),14,18-20,22,25,26 (twice); James 3:5,6; 4:1; in Colossians 3:5 , "mortify therefore your members which are upon the earth;" since our bodies and their "members" belong to the earth, and are the instruments of sin, they are referred to as such (cp. Matthew 5:29,30; Romans 7:5,23 , mentioned above); the putting to death is not physical, but ethical; as the physical "members" have distinct individualities, so those evils, of which the physical "members" are agents, are by analogy regarded as examples of the way in which the "members" work if not put to death; this is not precisely the same as "the old man," ver. 9, i.e., the old nature, though there is a connection; (b) metaphorically, "of believers as members of Christ," 1—Corinthians 6:15 (1st part); of one another, Romans 12:5 (as with the natural illustration, so with the spiritual analogy, there is not only vital unity, and harmony in operation, but diversity, all being essential to effectivity; the unity is not due to external organization but to common and vital union in Christ); there is stress in ver. 5 upon "many" and "in Christ" and "members;" 1—Corinthians 12:27 (of the "members" of a local church as a body); Ephesians 4:25 (of the "members" of the whole Church as the mystical body of Christ); in 1—Corinthians 6:15 (2nd part), of one who practices fornication.
Webster's Dictionary 
(1): ( n.) A part of an animal capable of performing a distinct office; an organ; a limb.
(2): ( n.) Hence, a part of a whole; an independent constituent of a body
(3): ( n.) A part of a discourse or of a period or sentence; a clause; a part of a verse.
(4): ( n.) Either of the two parts of an algebraic equation, connected by the sign of equality.
(5): ( v. t.) To remember; to cause to remember; to mention.
(6): ( n.) Any essential part, as a post, tie rod, strut, etc., of a framed structure, as a bridge truss.
(7): ( n.) Any part of a building, whether constructional, as a pier, column, lintel, or the like, or decorative, as a molding, or group of moldings.
(8): ( n.) One of the persons composing a society, community, or the like; an individual forming part of an association; as, a member of the society of Friends.
King James Dictionary 
MEM'BER, n. L. membrum.
1. A limb of animal bodies, as a leg, an arm, an ear, a finger, that is, a subordinate part of the main body. 2. A part of a discourse, or of a period or sentence a clause a part of a verse. Harmony in poetry is produced by a proportion between the members of the same verse, or between the members of different verses. 3. In architecture, a subordinate part of a building, as a frieze or cornice sometimes a molding. 4. An individual of a community or society. Every citizen is a member of the state or body politic. So the individuals of a club, a corporation or confederacy, are called its members. Students of an academy or college are its members. Professed christians are called members of the church. 5. The appetites and passions, considered as tempting to sin. Romans 7; Colossians 3
International Standard Bible Encyclopedia 
mem´bẽr ((1) יצר , yācur ; μέλος , mélos ; (2) שׁפכה , shāphekhāh , "membrum virile" ( Deuteronomy 23:1 )): The first Hebrew word is derived from a root meaning "to knead," "to mold in clay," "to create." It therefore denotes any feature or part of the body. "So the tongue also is a little member, and boasteth great things" ( James 3:5 ). "The members" is equivalent with "the body" (which see; compare Psalm 139:16 the King James Version). The members are not self-governing, but execute the orders of the mind, obeying either the lower nature in the commission of sin or iniquity, unrighteousness and uncleanness ( Romans 6:13 , Romans 6:19 ), or following the higher nature, the Divine impulses in the fulfilling of the law of Christ ( Romans 6:19 ).
By nature, the "law in my members" ( Romans 7:23 ) is opposed to the better nature ( James 4:1 ) until by "regeneration" (which see) this condition is changed, when the Spirit of Christ becomes the governing power, using our members, i.e. all our abilities, in the execution of His plans. This is not done while we remain passive, but only when we have actively presented or yielded our members to His service ( Romans 6:19 ). Therefore our bodies must not be desecrated by baser uses ( 1 Corinthians 6:15 , 1 Corinthians 6:19 , 1 Corinthians 6:20 ). The Lord Jesus illustrates the severe discipline which is needed to subdue the members of even the regenerate to perfect submission under the higher law of the Spirit by the simile of the right eye, which is to be plucked out, and the right hand, which is to be cut off ( Matthew 5:29 , Matthew 5:30 ), and Paul speaks of putting to death (the King James Version "mortifying") the "members which are upon the earth" ( Colossians 3:5 ).
It is the difference in character and gifts of individual Christians which leads Paul to speak of the variety of members, which, though of manifold functions, are equally important to the completeness of the body. It is thus in the manifold variety of the body of Christ ( 1 Corinthians 12:12-27; Ephesians 4:16 ), and Christians being members of Christ, who is the head ( Ephesians 1:22; Ephesians 4:15; Ephesians 5:23 ), are members one of another ( Romans 12:5; Ephesians 4:25 ).
In Deuteronomy 23:1 the Israelite Law against emasculation is referred to, and a religious disability is stated for the eunuch. Heathen Semites and other neighbors of Israel often castrated for religious purposes in the temple service of various divinities and for functions in princely palaces and harems. Heathen monarchs almost invariably had large numbers of these unfortunates, who frequently attained to positions of high power and responsibility. Herodotus states their frequent occurrence among the Persians ( Hist . vi. 32), and in the light of 2 Kings 20:18 and Daniel 1:3 it appears as not impossible that Daniel and his friends belonged to this class. In later years their existence is certain in Israel ( 1 Samuel 8:15 the Revised Version margin; Jeremiah 38:7; Matthew 19:12 ). See also Concision; Eunuch .
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
(in the plur. יְצַרַים , Yetsirim, Forms , Job 17:7; Μέλη , Parts , i.e. limbs) properly denotes a part of the natural body ( 1 Corinthians 12:12-25); figuratively, sensual affection, like a body consisting of many members ( Romans 7:23); also true believers, members of Christ's Mystical body, as forming one society or body, of which Christ is the head ( Ephesians 4:25).