focal length

noun

Definition of focal length

: the distance of a focus from the surface of a lens or curved mirror

Recent Examples of focal length from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'focal length.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of focal length

1682


FOCAL LENGTH Defined for English Language Learners

focal length

noun

Definition of focal length for English Language Learners

  • : the distance from the surface of a lens to the point of focus (sense 3)


Medical Dictionary

focal length

noun \ -ˌleŋ(k)th \

medical Definition of focal length

: the distance of a focus from the surface of a lens or concave mirror symbol f

Learn More about focal length


Seen and Heard

What made you want to look up focal length? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

ditzy

Get Word of the Day daily email!

Test Your Vocabulary

Find the Cousins

  • a-large-tree-with-many-branches
  • Which pair shares a common word ancestor?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!