samaya-sattva (Sanskrit). ‘Symbolic being’. In the course of tantric sādhanas, the practitioner generates an image of the focal deity—either as himself or in front—which is understood as a representation of that deity as a model for worship (pūjā) or personal transformation. The image is contrast to the actual presence of the deity, the jñāna-sattva.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)

dam tshig pa

[translation-san] samaya-sattva

[translation-eng] {Hopkins} [promise-word-having]; pledge being; one who has a promise (e.g. a tantric practitioner); pledge-being; symbolic being

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary