Archaic familiar term used by men to address a wife, lover, or close female friend. Not used in modern Japanese outside historical or poetic contexts.
An old poem says, 'The rain on the night when my love cannot sleep.'
Common modern 'you' or 'dear', but lacks the archaic poetic flavor and male-gendered familiarity of 吾妹.
my love; my dear; darling
Archaic kanji spelling; 吾 is an old first-person pronoun and 妹 here means a beloved woman.
Variant archaic spelling using 我 for the first-person element.
An Old Japanese contraction of 我が妹, “my beloved woman,” with 我 “I; my,” the possessive particle が, and 妹 “beloved woman.”