Requiring much physical effort; toilsome. / Mentally difficult; painstaking. / Industrious.

simple past tense and past participle of labor

Alternative form of laboured

(American spelling) Requiring a great deal of work, especially physical and manual effort versus capital.

With great expenditure of effort, in a manner requiring much labor.

The round sticker in the centre of a phonograph record that contains the record company's logo and information about the recording. / (by extension) The record company itself, as identified by its logo.

(chemistry) a laboratory designed for use with radioactive substances

(US), (Canada) The holiday marking the unofficial end of summer, held on the first Monday in September. / An annual holiday held on May 1 to celebrate the economic and social achievements of workers.

(physics, chemistry) An organic compound, containing an unpaired electron spin, that can be bonded to a molecule under investigation so as to be analysed using electron spin resonance spectroscopy

(US) Alternative spelling of labour force