thatch v.

Proto-Indo-European root meaning "to cover," especially with a roof. It forms all or part of: deck (n.) "covering over part of a ship;" deck (v.) "adorn;" deckle; detect; integument; protect; protection; stegosaurus; tegular; tegument; thatch; thug; tile; Tuileries.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sthag- "cover, conceal, hide;" Greek stegein "to cover," stegos "a roof;" Latin tegere "to cover," tegula "tile;" Lithuanian stėgti "to roof;" Old Norse þekja, Old English þeccan "thatch;" Dutch dekken, German decken "to cover, put under roof;" Irish tuigiur "cover," tech "house;" Welsh toi "thatch, roof," ty "house."

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.