1. (Science: biology, suffix) a suffix or terminal formative, used principally in biological terms, and signifying growth or formation. An immature precursor cell of the type indicated by the preceding word, for example; bioblast, epiblast, mesoblast, etc.
2. A violent gust of wind. A forcible stream of air from an orifice, as from a bellows, the mouth, etc. Hence: The continuous blowing to which one charge of ore or metal is subjected in a furnace; as, to melt so many tons of iron at a blast.
3. The terms hot blast and cold blast are employed to designate whether the current is heated or not heated before entering the furnace. A blast furnace is said to be in blast while it is in operation, and out of blast when not in use.