From , from , from līnea + -ālis.

• (America) IPA: /ˈlɪni.əl/
• (British) IPA: /ˈlɪniːəl/

lineal (not comparable)

1. Pertaining to a line.
2. Composed of lines; delineated.

   lineal designs

3. In the direction of a line; of a line; of or relating to a line; measured on, or ascertained by, a line; linear.

   lineal magnitude

4. Having the quality of proceeding, either physically or conceptually, according to a given rationale or other controlling principles of belief, opinion, practice, or phenomenon.
5. (anthropological and sociological) Having an ancestral relationship to mothers, fathers, grandparents, (etc.) and having a descendant relationship to sons, daughters, grandchildren (etc.), exclusive of collateral siblings.
   • 1689 December (indicated as 1690), [John Locke], chapter 1, in Two Treatises of Government: […], London: […] Awnsham Churchill, […], →OCLC ↗:

     the prime and ancient right of lineal succession

6. (anthropological, sociological, legal) Inheriting by direct descent; having the right by direct descent to succeed (to).
   • 1693 (first performance), John Dryden, “To My Dear Friend Mr. Congreve, on His Comedy, Call’d, The Double-Dealer ↗”, in The Double-Dealer. A Comedy, London: […] Jacob Tonson […], published 1735, →OCLC ↗, Act I,:

     Oh that your Brows my Laurel had ſuſtain'd, / Well had I been depos'd, if You had Reign'd! / The Father had deſcended for the Son; / For only you are lineal to the Throne.

• collateral

• line
• linear
• lineage