focal

focal is defined in Webster's Unabridged Dictionary (1913) with 1 sense, and appears in Roget's Thesaurus (1911) with 40 related terms. The full text of each entry is reproduced verbatim below.

Definitions

  1. 1.Belonging to,or concerning, a focus; as, a focal point. Focal distance, or length,of a lens or mirror (Opt.), the distance of the focus from the surface of the lens or mirror, or more exactly, in the case of a lens, from its optical center. --Focal distance of a telescope, the distance of the image of an object from the object glass.

Source: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).

Synonyms

Related questions

Sources

  • Definitions: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).
  • Synonyms & antonyms: Roget's Thesaurus, 1911 edition (public domain, via Project Gutenberg eBook #10681).
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