Vine's Expository Dictionary of OT Words 
Yachad ( יַחַד , Strong'S #3162), “together; alike; all at once; all together.” Yachad appears about 46 times and in all periods of biblical Hebrew.
Used as an adverb, the word emphasizes a plurality in unity. In some contexts the connotation is on community in action. Goliath challenged the Israelites, saying: “I defy the armies of Israel this day; give me a man, that we may fight together” (1 Sam. 17:10). Sometimes the emphasis is on commonality of place: “… And it came to pass, that they which remained were scattered, so that two of them were not left together” (1 Sam. 11:11). The word can be used of being in the same place at the same time: “And he delivered them into the hands of the Gibeonites, and they hanged them in the hill before the Lord: and they fell all seven together …” (2 Sam. 21:9). In other passages yachad means “at the same time”: “O that my grief were thoroughly weighed, and my calamity laid in the balances together!” (Job 6:2).
In many poetic contexts yachad is a near synonym of kullam , “altogether.” Yachad,— however, is more emphatic, meaning “all at once, all together.” In Deut. 33:5 (the first biblical occurrence) the word is used emphatically, meaning “all together,” or “all of them together”: “And he was king in Jeshurun, when the heads of the people and the tribes of Israel were gathered together.” Cf.: “Surely men of low degree are vanity, and men of high degree are a lie: to be laid in the balance, they are altogether lighter than vanity” (Ps. 62:9). In such contexts yachad emphasizes the totality of a given group (cf. Ps. 33:15). Yachad also sometimes emphasizes that things are “alike” or that the same thing will happen to all of them: “The fool and the stupid alike must perish” (Ps. 49:10, RSV).
Yachad ( יַחַד , Strong'S #3162), “all alike; equally; all at once; all together.” The second adverbial form, yachdaw appears about 92 times. It, too, speaks of community in action (Deut. 25:11), in place (Gen. 13:6—the first biblical appearance of this form), and in time (Ps. 4:8). In other places it, too, is synonymous with kullam , “altogether.” In Isa. 10:8 yachdaw means “all alike,” or “equally”: “Are not my princes altogether kings?” In Exod. 19:8 this word implies “all at once” as well as “all together”: “And all the people answered together, and said.…” The sense “alike” appears in Deut. 12:22: “Even as the roebuck and the hart is eaten, so thou shalt eat them: the unclean and the clean shall eat of them alike.”
Yachad means “to be united, meet.” This verb appears in the Bible 4 times and has cognates in Aramaic, Ugaritic, Arabic, Ethiopic, and Akkadian. One occurrence is in Gen. 49:6: “O my soul, come not thou into their secret; unto their assembly, mine honor, be not thou united.…”
Yâchı̂yd ( יָחִיד , Strong'S #3173), “very self, only; solitary; lonely.” This word appears 12 times as a noun or as an adjective. Yâchı̂yd has cognates in Ugaritic, Aramaic, and Syriac. The word can be used meaning “self, my soul”: “Deliver my soul from the sword, my life [NASB, “only life”; KJV, “darling”] from the power of the dog” (Ps. 22:20, RSV; cf. Ps. 35:17).
Sometimes this word means “only”: “Take now thy son, thine only son Isaac, whom thou lovest …” (Gen. 22:2—the first biblical occurrence of the word). In two passages this word means “solitary” or “lonely”: “Turn thee unto me, and have mercy upon me; for I am desolate [RSV, “lonely”] and afflicted” (Ps. 25:16; cf. Ps. 68:6).
The noun yâchı̂yd occurs only once to mean “unitedness.” David said to the Benjaminites: “If ye be come peaceably unto me to help me, mine heart shall be knit unto you [I am ready to become one (or united) with you] …” (1 Chron. 12:17). This usage of the word as a substantive is unusual.
Vine's Expository Dictionary of NT Words 
used in connection with place, in John 21:2; Acts 2:1 (in the best texts), RV, "together" (AV, "with one accord," translating the inferior reading homothumadon: see Accord , A), is used without the idea of place in John 4:36; 20:4 .
"at once," is translated "together" in Romans 3:12; 1—Thessalonians 4:17; 5:10 . See Early , Note, Withal.
Luke 23:18Once 1—Thessalonians 5:11 Luke 23:12 Luke 24:14 Matthew 22:34 Luke 17:35 Acts 1:15 2:44 Acts 3:1 1—Corinthians 7:5 14:23Place Acts 14:1
King James Dictionary 
1. In company. We walked together to the wood. 2. In or into union.
The king joined humanity and policy together.
3. In the same place as, to live together in one house. 4. In the same time as, to live together in the same age. 5. In concert as, the allies made war upon France together. 6. Into junction or a state of union as, to sew, knit, pin or fasten two things together to mix things together.
Together with, in union with in company or mixture with.
Take the bad together with the good.
Webster's Dictionary 
(1): ( prep.) In company or association with respect to place or time; as, to live together in one house; to live together in the same age; they walked together to the town.
(2): ( prep.) In or into union; into junction; as, to sew, knit, or fasten two things together; to mix things together.
(3): ( prep.) In concert; with mutual cooperation; as, the allies made war upon France together.