To find out or observe (someone or something, especially if not easy to see) by spying or looking; to catch sight of; to see; to spot.
To see (someone or something) without foreplanning or unexpectedly.
To notice or view, especially carefully or with attention to detail.
To take note of and celebrate (a holiday or similar occurrence); to follow (a type of time or calendar reckoning).
To comment on something; to make an observation.
To follow or obey the custom, practice, or rules (especially of a religion).