List of direct line synonyms and direct line related words.
affiliation, air line, apparentation, axis, beeline, birth, blood, bloodline, branch, breed, chord, common ancestry, consanguinity, derivation, descent, diagonal, diameter, directrix, distaff side, edge, extraction, family, female line, filiation, great-circle course, house, line, line of descent, lineage, male line, normal, perpendicular, phylum, race, radius, radius vector, right line, secant, seed, segment, sept, shortcut, side, spear side, spindle side, stem, stirps, stock, straight, straight course, straight line, straight stretch, straightaway, strain, streamline, succession, sword side, tangent, transversal, vector