-blast. A suffix meaning an immature precursor cell of the type indicated by the preceding word. [G. blastos, germ]. immature precursor cell type; the cell type is denoted by the preceding syllables, e.g. osteoblast.
(plural defining moments) A moment in time that defines something, such as a person's success or failure, achievement or demise, talent, etc. A point at which the essential nature or character of a person, group, etc., is revealed or identified.
an indefinitely short period of time; instant: I'll be with you in a moment. the present time or any other particular time (usually preceded by the): He is busy at the moment. a definite period or stage, as in a course of events; juncture: at this moment in history. importance or consequence: a decision of great moment.