sol ‧ stice /ˈsɒlstəs, ˈsɒlstɪs $ ˈsɑːl-/ BrE AmE noun [countable]
[ Date: 1200-1300 ; Language: Old French ; Origin: Latin solstitium , from sol 'sun' + status , past participle of sistere 'to come to a stop' ]
the time when the sun is furthest north or south of the ↑ equator
the summer/winter solstice (=the longest or shortest day of the year)
⇨ equinox