Celebrated time of year, so Celt is dancing (8)

I believe the answer is:
solstice
'celebrated time of year so celt is dancing' is the definition.
I can't judge whether this definition defines the answer.
'so celt is dancing' is the wordplay.
'dancing' indicates an anagram.
'celt'+'is'='celtis'
'celtis' is an anagram of 'lstice'.
'so'+'lstice'='SOLSTICE'
Can you help me to learn more?
(Other definitions for solstice that I've seen before include "it occurs biannually" , "When night and day are most unequal" , "21 June or 22 December?" , "Time of year when sun is furthest from equator" , "Seasonal turning point" .)
