Definition of Baker day in English:

Baker day

Pronunciation /ˈbeɪkə deɪ/

noun

informal
  • In the United Kingdom: one of five days in the state school year in which the school is closed to pupils so that teachers can attend training and perform administrative tasks.

    INSET day is now the usual term.

Origin

1980s; earliest use found in The Times Educational Supplement. From the name of Kenneth Wilfred Baker (b. 1934), British Education Secretary, who introduced the scheme + day.