English

Verb

thack ‎(third-person singular simple present thacks, present participle thacking, simple past and past participle thacked)

1. (transitive) To strike; thump; thwack.

Etymology 2

From Middle English thacce, from thakken ‎(“to stroke”). See above.

Noun

thack ‎(plural thacks)

1. A stroke; a thwack.

Etymology 3

From Middle English thak, thakk, thakke, from Old English þæc, from Proto-Germanic *þaką, from Proto-Indo-European *teg-. Cognate with Dutch dak, Low German Dack, Danish tag ‎(“roof”), German Dach ‎(“roof”), Old Norse þak ‎(“thatch, roof”). Akin to Latin toga ‎(“garment”) and Ancient Greek στέγος ‎(stégos, “roof”)^[1]. See also thatch.

Noun

thack ‎(plural thacks)

1. the weatherproof outer layer of a roof, often thatch specifically
   • 1952, L.F. Salzman, Building in England, p. 223.

     This outer layer was generically known as 'thack', but, owing to the fact that the vast majority of buildings in early times were covered with a thacking of straw or some similar material, 'thatch' gradually acquired its modern restricted significance of straw, or reed, heling.

Verb

thack ‎(third-person singular simple present thacks, present participle thacking, simple past and past participle thacked)

1. To cover a roof with thack.

References

1. ↑ “tag” in Ordbog over det danske Sprog