a plane that is perpendicular to the axis of a lens, mirror, or other optical system and at which rays diverging from a focal point are deviated parallel to the axis or at which rays parallel to the axis are deviated to converge to a focal point.
Principal vs. PrincipleIs the head of a school called a principal or a principle? These two words are frustratingly similar, leaving even the most experienced English speakers to second-guess which word means what. So, in today’s lesson, we’ll discuss the distinct meanings between these easy-to-confuse terms— and leave you with a little trick to help differentiate between your principals and your principles. What is a principal? A …
Hone In vs. Home InDoes a plane home in on a target or hone in on it? Does a musician hone her skills or home them? Are these two verbs interchangeable or do they have discrete meanings? Today we explore the origins and uses of hone and home. Hone entered English as a noun for a pointed rock used as a landmark. In the 1400s, it began to be …
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019