—n. 1. a submarine.
2. a substitute.
3. a submarine sandwich. See hero sandwich. 4. a subcontractor.
5. a sublieutenant.
6. a subordinate.
7. a subaltern.
8. Brit.an advance against one's wages, esp. one granted as a subsistence allowance.
9. Photog.a substratum.
—v.i. to act as a substitute for another.
—v.t. Photog.to coat (a film or plate) with a substratum.
supplemental unemployment benefits.
1. a prefix occurring originally in loanwords from Latin (subject; subtract; subvert; subsidy); on this model, freely attached to elements of any origin and used with the meaning “under,” “below,” “beneath” (subalpine; substratum), “slightly,” “imperfectly,” “nearly” (subcolumnar; subtropical), “secondary,” “subordinate” (subcommittee; subplot).
2. Chem. a. a prefix indicating a basic compound: subacetate; subcarbonate; subnitrate. b. a prefix indicating that the element is present in a relatively small proportion, i.e., in a low oxidation state: subchloride; suboxide.Also,su-,suc-,suf-,sug-,sum-,sup-,sur-,sus-.