*(s)teg-

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.

1810, in paper-making, "rectangular frame on which the pulp is placed," from German deckel "lid, little cover," diminutive of decke "cover," from Old High German decchen "to cover," from Proto-Germanic *thakjan, from PIE root *(s)teg- "to cover." Meaning "rough or raw edge of paper" is by 1858.