parfocality
/ˌpɑːfəʊˈkalɪti/Optics
noun
The property of being parfocal.
Origin
1950s; earliest use found in Science. From parfocal + -ity; compare -ality.
- keep something to oneself
- keep something under one's hat
- keep something up
- keep step
- keep tabs (or a tab) on
- keep the ball rolling
- keep the bastards honest
- keep the field
- keep the peace
- keep the pot boiling
- keep (the) score
- keep the wolf from the door
- keep time
- keep to
- keep to oneself
- keep up (also keep up with)
- keep up appearances
- keep up with
- keep up with the Joneses
- keep watch
- keep wicket
- keep your hair on!
- keep your pecker up
- keep your shirt on
- keepy-up