沖
チュウ, おき, おきつ, ちゅう.する, わく
open sea, offing, rise high into sky
JLPT1 G7 S7 F929
中# center/middle + 水 water → extract flavor from tea by infusing in hot water. In Japan, however, 沖 has been reinterpreted as 中 center/middle + 水 water → point midway between the shore and deep waters of a lake or the open waters of a sea → *offshore*; *offing*; *open sea*.
[Full Kanji Etymology List]