noun
Thursday, Friday, and Saturday
Refers to the three-day period from Thursday to Saturday, often used in scheduling contexts.
来週の木金土は出張です。
I'll be on a business trip next Thursday, Friday, and Saturday.
Weekend; 木金土 is the lead-up to the weekend, not the weekend itself.
Compound of the abbreviated weekday names 木 (Thursday), 金 (Friday), and 土 (Saturday).