お母ん is read as おかん (okan) and means mom.
おかん
okan
おかあさん
wife
おばーさん
grandmother
かあさん
mother
おかあさま
はは
ふぼ
father and mother
ぼし
mother and child
ぼこく
one's home country
ぼこくご
language of one's country
ぼこう
alma mater
ははのひ
Mother's Day (2nd Sunday of May)
ぼしねんきん
widowed mother's allowance