Definition of "filar" []

• Of or relating to a thread. (adjective)
• Having fine threads across the field of view for measuring small distances, as in the eyepiece of a telescope. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Over 10,000 filar-micrometer and red light CCD measurements of Mars' north polar cap have been taken over the past 40 years, and they show that it has been shrinking."
• "For several thousand years the stars have been called "fixed," but the fine rulings of the filar micrometer tell a different story."
• "Place the filar micrometer and the stage micrometer in their respective positions."