Archaic female term of endearment for a husband, lover, or close male friend. Not used in modern Japanese outside of historical or literary contexts.
In an old letter it is written, 'My love, my feelings for you will never change.'
my friend; comrade
Archaic male term for a close male friend. Like sense 1, it is obsolete in modern speech and appears only in historical or literary works.
It is said that warriors called each other 'seko' (my friend).
Most common kanji spelling for this archaic term.
Alternate kanji spelling, also archaic.
Rarely used kanji form.
The exact derivation is uncertain. The kanji 背 (back, stature) and 子 (child) are conventionally associated with the meaning, but the historical origin of the reading せこ is unclear.