Getz (2004: p. 760) provides a generalist Western Buddhist encyclopedic definition:
Sentient beings is a term used to designate the totality of living, conscious beings that constitute the object and audience of Buddhist teaching. Translating various Sanskrit terms (jantu, bahu jana, jagat, sattva), sentient beings conventionally refers to the mass of living things subject to illusion, suffering, and rebirth (Saṃsāra). Less frequently, sentient beings as a class broadly encompasses all beings possessing consciousness, including Buddhas and Bodhisattvas.
 Getz, Daniel A. (2004). "Sentient beings"; cited in Buswell, Robert E. (2004). Encyclopedia of Buddhism. Volume 2. New York, USA: Macmillan Reference USA. ISBN 0-02-865720-9 (Volume 2): pp.760