noun
nesting hole; burrow; den
Refers to a hole or tunnel dug by an animal for nesting or shelter. Common for small mammals, birds, and insects.
ウサギが巣穴から顔を出した。
A rabbit poked its head out of the burrow.
キツツキは木に巣穴を掘る。
Woodpeckers drill nesting holes in trees.
Rarely used kanji form; 孔 means 'hole' but is less common than 穴 in this compound.
Compound of 巣 (su, 'nest') and 穴 (ana, 'hole'). The reading すあな is a straightforward combination; the alternative reading そうけつ is obsolete.