A large class of irregular English verbs are characterized by having /ɔːt/ in their pronunciation in the past tense and past participle. In most cases, /ɔːt/ is spelled as “ought”:
bring – brought – brought
buy – bought – bought; also “overbuy”
fight – fought – fought; also “outfight”
seek – sought – sought
think – thought – thought; also “bethink”, “misthink”, “rethink”
* “Beseech” is an uncommon (and somewhat dated) verb meaning “to beg, to request in an anxious way”.
There are two more verb roots following the same pattern but with /ɔːt/ being spelled as “aught”:
teach – taught – taught; also “misteach” and “reteach”