labour, labor, laborious

The spelling labour is preferred in Canada, although labor is also accepted.

• His hands worn by years of labour, his face creased by years of laughter, the old man prepared to face another day.
• Marsha was in labour for 12 hours before giving birth to her second child.

The u is dropped in laborious.

• Mike and Andrée managed to avoid the laborious task of spring cleaning well into autumn.