(typography) each mark of the pairs of iteration marks ゝ/ゞ and ヽ/ヾ, respectively used to repeat 清音 (seion)/濁音 (dakuon) hiragana and katakana

Have a nice day!

the same criminal

(literally) know the other side and yourself, a hundred battles will not be perilous

one for all, all for one

(literally) plan your day during the morning, plan your year during New Year's / early planning is the key to success

kill two birds with one stone, do one task and finish two or more goals (literally, “one stone, two birds”)

(obsolete) being surprised twice / (obsolete) more specifically, describes the appearance of a woman who has a beautiful figure from behind but has an ugly face

(grammar) a verbal conjugation class in which the verb stem ends in -i and consists of four alternating bases: -i, -iru, -ire, and -iyo/-iro

Kyūjitai form of 三位一体 (“Trinity”)