Time: half-hour, quarter-hour

Ùine: leth-uair, cairteal

Like English, the clock is broken up into quarterly chunks. 

leth-uair
a half hour
leth-uair an dèidh
half past
an dèidh
after
cairteal
a quarter
cairteal an dèidh
quarter past
cairteal gu
quarter to
gu bhith
almost
timcheall air
about

Às dèidh  is commonly used for after in Gaelic too. We will use  an dèidh  on this site.