their

Belonging to, from, of, or relating to, them (plural).

they will meet tomorrow at their convenience

this is probably their cat

For all things, even Celestial Luminaries, much more atmospheric meteors, have their rise, their culmination, their decline.

For Liverpool, their season will now be regarded as a relative disappointment after failure to add the FA Cup to the Carling Cup and not mounting a challenge to reach the Champions League places.

Belonging to someone (one person, singular), or occasionally to something.

There's not a man I meet but doth salute me As if I were their well-acquainted friend […]

Place the casualty on their back with feet and legs raised—this is called the shock position. [emphasis in original] Once the casualty is positioned, cover them to preserve body heat, but do not overheat.

I prefer to think that birds have a sufficiently developed sense of humour to enjoy the spectacle of a human being hunched beneath a bush kissing the back of their hand.

‘I mean ... if somebody made a mistake,’ Harry went on, ‘and let something slip, I know they didn’t mean to do it. It’s not their fault,’ he repeated, again a little louder than he would usually have spoken.

Variante von thereMisspelling of there.

Variante von they’reMisspelling of they’re.