Karuna - Karuna

Japanese: カルナー - かるなー

…The original meaning is friendship, fraternity, derived from mitra (friend), but in Buddhism it is especially respected as mercy. Sanskrit karuṇā: compassion, mercy. It is said that the original meaning was groaning, and from suffering and lamenting (the pain of others as if it were one's own), it came to mean sympathy, pity. …

From "Mercy"

...The heart of compassion and mercy preached in Buddhism. In Sanskrit it is called maitrī or karuṇā. When distinguishing between mercy and compassion, mercy corresponds to maitri and compassion corresponds to karuṇā. ...

*Some of the terminology explanations that mention "Karuna" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…原義は〈ミトラmitra(友)〉に由来する〈友情･友愛〉であるが，仏教では，とくに〈いつくしみ〉として尊重される。　梵巴〈カルナーkaruṇā〉：〈悲･慈悲〉。原義は〈うめき〉であるとも言われ，〈(他者の苦痛をわがこととして)苦しむこと･嘆き悲しむこと〉から，〈同情･あわれみ〉を意味するようになった。…