The Collaborative International Dictionary of English v.0.48:

Ashtoreth \Ash"to*reth\, n.; pl. Ashtaroth.
   The principal female divinity of the Ph[oe]nicians, as Baal
   was the principal male divinity. --W. Smith.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ashtoreth
    n 1: an ancient Phoenician goddess of love and fertility; the
         Phoenician counterpart to Ishtar [syn: Astarte,
         Ashtoreth]

Easton's 1897 Bible Dictionary:

Ashtoreth
   the moon goddess of the Phoenicians, representing the passive
   principle in nature, their principal female deity; frequently
   associated with the name of Baal, the sun-god, their chief male
   deity (Judg. 10:6; 1 Sam. 7:4; 12:10). These names often occur
   in the plural (Ashtaroth, Baalim), probably as indicating either
   different statues or different modifications of the deities.
   This deity is spoken of as Ashtoreth of the Zidonians. She was
   the Ishtar of the Accadians and the Astarte of the Greeks (Jer.
   44:17; 1 Kings 11:5, 33; 2 Kings 23:13). There was a temple of
   this goddess among the Philistines in the time of Saul (1 Sam.
   31:10). Under the name of Ishtar, she was one of the great
   deities of the Assyrians. The Phoenicians called her Astarte.
   Solomon introduced the worship of this idol (1 Kings 11:33).
   Jezebel's 400 priests were probably employed in its service (1
   Kings 18:19). It was called the "queen of heaven" (Jer. 44:25).