directrix

English

Etymology

Learned borrowing from Latin dīrēctrīx. By surface analysis, direct +‎ -trix.

Pronunciation

• Audio (US):

  (file)

Noun

In this picture of an ellipse, a parabola, and an hyperbola, the black line is their shared directrix.

directrix (plural directrixes or directrices)

1. A female who directs; a directress.
2. (geometry) A line used to define a curve or surface; especially a line, the distance from which a point on a conic has a constant ratio to that from the focus.

Derived terms

• conic section directrix
• graph directrix
• ruled surface directrix

Translations

a line used to define a curve or surface

• Dutch: richtlijn (nl) m or f
• Finnish: johtosuora
• French: directrice (fr) f
• Greek: διευθετούσα (el) f (diefthetoúsa)
• Polish: kierownica (pl) f
• Spanish: directriz (es) f
• Tamil: இயக்குவரை (ta) f (iyakkuvarai)

a female who directs — see directress

References

• “directrix, n.”, in OED Online ⁠, Oxford: Oxford University Press, launched 2000.

Anagrams

• creditrix