Morrish Bible Dictionary 
These were made of rams' horns and perhaps of the horns of other animals. They were used on joyful occasions, and at the wars. There were two trumpets made of silver which the priests used, and instructions were given as to blowing different sounds for calling the princes together, or for summoning all the congregation, or as an alarm for war. Numbers 10:1-10 : cf. 1 Corinthians 14:8 . At the dedication of the temple Solomon had a hundred and twentypriests sounding with trumpets. 2 Chronicles 5:12 .
The use of trumpets set forth the public proclamation of God's rights in His people, whether in their direction or in their relationship with Him.
At the giving of the law there was a loud voice of the trumpet proceeding from the mount, exceeding loud; so that all the people trembled. Exodus 19:16,19; Hebrews 12:19 .
When the Lord Jesus comes to fetch His saints it will be with the voice of the archangel and with the trump of God. 1 Thessalonians 4:16 . The 'last trump' will sound at the resurrection of the saints. 1 Corinthians 15:52 . In the Roman army, when it was about to start, the trumpet sounded three times: at the first trumpet they pulled down their tents: at the second they put themselves in order; and when the last sounded they started.
In the judgements that are to fall upon the earth, as foretold in the Revelation, the Seven Seals introduce the Seven Trumpets: the first four fall upon the Roman earth, and refer to the state and circumstances of men; the latter three trumpets refer to the East, and fall upon the persons themselves. The Trumpets come in between the Seals and the Vials. Revelation 8:2 Revelation 9:14 .
Easton's Bible Dictionary 
Numbers 10:2 Joshua 6:8 Leviticus 23:24 25:9 1 Chronicles 15:24 2 Chronicles 29:27 Psalm 81:3 98:6
"Trumpets" are among the symbols used in the Book of Revelation ( Revelation 1:10; 8:2 ). (See Horn .)
Webster's Dictionary 
(n. pl.) A plant (Sarracenia flava) with long, hollow leaves.