一ひとつ心こころ

Meanings

one mind; wholeheartedness; single-hearted devotion

Refers to a state of being of one mind, wholeheartedly devoted to something, or acting with complete sincerity and unity of purpose. Often used in contexts of dedication, prayer, or collective resolve.

彼かれは一ひとつ心こころで研けん究きゅうに打うち込こんだ。
He devoted himself wholeheartedly to his research.
皆みなが一ひとつ心こころになって被ひ災さい地ちを支し援えんした。
Everyone came together as one to support the disaster area.

Kanji

一one, one radical (no.1)
心heart, mind, spirit

Related words

一いっ心しん
Similar meaning of wholeheartedness, but 一心 is more common and can also mean 'one heart' in a more abstract or religious sense. 一つ心 emphasizes a unified, collective mindset.
心こころを一ひとつにする
A common phrase meaning 'to unite one's hearts' or 'to be of one mind'. 一つ心 is a noun form that encapsulates this idea.

Built from

一ひと+心こころ

Written forms

一ひとつ心こころ
Standard kanji-kana mixed spelling.
ひとつ心こころ
Kana spelling for the numeral part; less common but still encountered.

Etymology

Compound of 一つ (ひとつ, 'one') and 心 (こころ, 'heart, mind'). The exact historical derivation is uncertain, but the word literally means 'one heart/mind' and has been used to express unity of purpose or wholeheartedness.