IPA: /ˈwʊl.sæk/
KK: /ˈwʊlˌsæk/
A bag used to hold wool or the official seat of the Lord Chancellor in the House of Lords.
The Lord Chancellor sat on the woolsack during the session in the House of Lords.
Woolsack → The word originates from Old English 'wull' (meaning wool) and 'sæc' (meaning sack). A woolsack is literally a sack filled with wool, historically used as a seat in the House of Lords in England.
Picture a 'sack' ('sæc') filled with 'wool' ('wull') — that's why a woolsack is a sack of wool.
No commonly confused words.