Flexitime is a work system. You still work a set number of hours in the week or the month, but you can change when those hours sit in the day: start earlier, start later, finish earlier, finish later, inside the rules your workplace sets. Often the middle of the day is fixed — everyone must be there — and only the edges are yours. It is the usual British spelling; American English most often writes flextime. Offices like it for the school run, or so people can miss the worst traffic. Though actually, it does not mean “come when you like,” and it does not mean fewer hours. You still owe the total. If nobody is counting the hours, you just have a loose day; that is not flexitime. You will meet the word on job pages and in office talk more than in stories.

彈性工時（台灣職場就這麼說；美式拼法常寫 flextime）