和讃 is a general term for Japanese Buddhist hymns, while 来迎和讃 specifically praises the coming of the Buddha.
来迎 refers to the coming of the Buddha to welcome the dying, while 来迎和讃 is the hymn about that event.
Compound of 来迎 (raigō, 'coming of the Buddha') and 和讃 (wasan, 'Japanese hymn'). The exact historical derivation is uncertain, but the term is traditionally associated with Minamoto no Makoto.