iso-, is-

(Greek: equal; by extension: same, similar, alike; normally used as a prefix)

Used in numerous terms, nearly all scientific; denoting: equality, similarity, uniformity, or identity; the second element being properly and usually of Greek origin, rarely of Latin [the proper prefix in the latter case being equi-]. In biology, denoting for or from different individuals of the same species). For a large list of iso- opposites or antonyms, see aniso-.

A toxin from an individual that is toxic to other individuals of the same species; homeotoxin.
isotropic, isotropy
1. Possessing similar qualities in every direction.
2. Having equal refraction.
3. Having physical properties that do not vary with direction.
isozoic (adjective) (not comparable)
Characterized by or indicating the same forms of animal life: Isozoic characteristics were found in the animal life of the ocean.
isozooid (s) (noun), isozooids (pl)
An individual of a compound or “colonial” animal organism, not differentiated from the rest: An isozooid resembles its parent, whereas an "allozooid" differs from the parent.

Inter-related cross references, directly or indirectly, involving word units dealing with "equal, identical, same, similar": auto-; emul-; equ-, equi-; homeo-; homo-; pari-; peer; rhomb-; syn-; tauto-.