Merriam-Webster's Advanced Learner's Dictionary:
Thursday
Thurs·day /ˈɵɚzˌdeɪ/ noun, pl -days : the day between Wednesday and Friday
[count]
• He was late last Thursday.
• (Brit) We went on the Thursday and returned on the Saturday.
• The class meets on Thursdays. [=every Thursday]
[noncount]
• We went on Thursday and returned on Saturday.
• She will arrive on Thursday. = (US) She will arrive Thursday.
- abbr. Thurs. or Thur. or Th.;
- Thurs·days /ˈɵɚzˌdeɪz/ adv
• The class meets Thursdays. [=every Thursday]