fore-deck (n.)

Middle English for-, fore-, from Old English fore-, often for- or foran-, from fore (adv. & prep.), which was used as a prefix in Old English as in other Germanic languages with a sense of "before in time, rank, position," etc., or designating the front part or earliest time.

mid-15c., dekke, "covering extending from side to side over part of a ship," from a nautical use of Middle Dutch dec, decke "roof, covering," from Proto-Germanic *thakam (source also of thatch (n.)), from PIE root *(s)teg- "to cover."

Sense extended early in English from "covering" to "platform of a ship." Meaning "pack of cards necessary to play a game" is from 1590s, perhaps because they were stacked like decks of a ship. Tape-deck (1949) is in reference to the flat surface of old reel-to-reel tape recorders. 

Deck-chair (1844) so called because they were used on ocean liners. On deck (by 1740) was in nautical use especially "ready for action or duty;" extended sense in baseball, of a batter waiting a turn at the plate, is by 1867. To clear the deck (1852) is to prepare a ship for action; it is perhaps a translation of French débarasser le pont.