What does "earth day" mean?

A day in Earth time; the period it takes planet Earth to revolve once; a period of 24 hours.

Earth day

Common synonyms include: curriculum focus, eco holiday, education theme, environmental holiday, green holiday, teaching theme.

name, noun

name, noun ·Rare ·Advanced level

Noun

1
A day in Earth time; the period it takes planet Earth to revolve once; a period of 24 hours.

Proper Noun

1
April 22; Created in 1970, global day of observance of the need to protect the earth. North-American
2
March 21st. US, obsolete