first lull of the year; New Year's calm
Refers to the first calm (windless) period of the new year, often associated with New Year's Day. A seasonal word (kigo) used in haiku and traditional contexts.
On New Year's morning, I wished for peace this year while looking at the calm sea of the first lull.
Compound of 初 (hatsu, 'first') and 凪 (nagi, 'calm, lull'). The exact historical origin is uncertain, but it is a traditional seasonal term.