healing is the process of becoming or making somebody or something healthy again, and, as the Oxford Advanced Learner's Dictionary adds, the process of getting better after an emotional shock.
Dictionaries give the noun both a physical and an emotional reach. Cambridge Dictionary defines it as the process of becoming well again, especially after a cut or other injury, or of making someone well again, and its usage examples run from covering wounds with a gauze dressing while healing occurs to fostering healing in a community. Dictionary.com glosses the noun more briefly as the act or process of regaining health. Oxford's collocations show the same span: the word is used before nouns such as process and ritual, and after nouns such as faith and wound, giving the healing process, faith healing and wound healing.
Healing also works as an adjective. Cambridge defines it as helping to make someone well again, as in healing powers or healing properties, while Dictionary.com gives the adjective two senses, curing or curative, and growing sound, getting well or mending. Dictionary.com records the word as first recorded before 1000, traces it through Middle English to Old English hǣlinge, and analyses it as the verb heal plus the suffix -ing.