お母さん

Etymology
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Attested in Osaka and Kyoto, with rare use in Edo (Tokyo), from the late, especially among upper-middle class households in Osaka.

Usage became widespread in the 20th century after the Ministry of Education adopted and  for use in 尋常小学読本 (Jinjō shōgaku dokuhon “Standard elementary school reader”, 1903).

Noun

 * 1)  mother; one's mother