One who cradles; a person or thing that holds or rocks something gently, or rocks a cradle.
From 'cradle' (verb: to rock gently) + '-er' (suffix indicating one who does something). This agent noun follows standard English patterns for creating occupational or descriptive nouns from verbs.
A cradler was often the grandmother or eldest female relative whose specific job was soothing babies—this role was so important that languages created a word specifically for the person who did this essential comfort work.
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