/ Thesaurus / B Synonyms of basic slag Find synonyms for: Noun1. basic slag, slag, scoria, drossusage: slag produced in making steel; low in silica but having large amounts of calcium phosphate; useful as fertilizerWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language