
[Middle English caustik, from Latin causticus, from Greek kaustikos, from kaustos, from kaiein, kau-, to burn.]
caustically caus'ti·cal·ly adv.Describing a substance that is strongly alkaline (e.g. caustic soda).
Biting, penetrating, possibly painful — that's how Richard Pryor's humor was described in an early obituary:
"Richard Pryor, the caustic yet perceptive actor-comedian who lived dangerously close to the edge both on stage and off, died Saturday. He was 65."
Link: The Boundless Gifts of Richard Pryor
Posted December 12, 2005.
See our Word Overheard blog to see interesting uses of strange words.
adjective
Definition: burning, corrosive
Antonyms: calm, mild, soothing
adj
Definition: sarcastic
Antonyms: kind, nice, unsarcastic
1. burning or corrosive; destructive to tissue.
2. having a burning taste.
3. a corrosive or escharotic agent.

In differential geometry and geometric optics, a caustic is the envelope of rays either reflected or refracted by a manifold. It is related to the concept of caustics in optics. The ray's source may be a point (called the radiant) or infinity, in which case a direction vector must be specified.
More generally, especially as applied to symplectic geometry and singularity theory, a caustic is the critical value set of a Lagrangian mapping (π ○ i) : L ↪ M ↠ B; where i : L ↪ M is a Lagrangian immersion of a Lagrangian submanifold L into a symplectic manifold M, and π : M ↠ B is a Lagrangian fibration of the symplectic manifold M. The caustic is a subset of the Lagrangian fibration's base space B.[1]
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A catacaustic is the reflective case.
With a radiant, it is the evolute of the orthotomic of the radiant.
The planar, parallel-source-rays case: suppose the direction vector is
and the mirror curve is parametrised as
. The normal vector at a point is
; the reflection of the direction vector is (normal needs special normalization)

Having components of found reflected vector treat it as a tangent

Using the simplest envelope form


which may be unaesthetic, but
gives a linear system in
and so it is elementary to obtain a parametrisation of the catacaustic. Cramer's rule would serve.
Let the direction vector be (0,1) and the mirror be
Then



and
has solution
; i.e., light entering a parabolic mirror parallel to its axis is reflected through the focus.
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Dansk (Danish)
adj. - sarkastisk, kaustisk, ætsende
n. - causticum (ætsmiddel)
idioms:
Nederlands (Dutch)
brandend, bijtend
Français (French)
adj. - (Chim, fig) caustique
n. - causticité, substance caustique, hydroxyde, courbe/surface caustique
idioms:
Deutsch (German)
adj. - ätzend, bissig
n. - Ätzmittel, (Med.) Kaustikum
idioms:
Ελληνική (Greek)
adj. - (χημ.) καυστικός, (μτφ.) δηκτικός, σαρκαστικός
idioms:
idioms:
Português (Portuguese)
adj. - cáustico
idioms:
Русский (Russian)
каустический, едкий
idioms:
Español (Spanish)
adj. - cáustico
n. - cáustico
idioms:
Svenska (Swedish)
adj. - brännande, skarp
中文(简体)(Chinese (Simplified))
腐蚀性的, 刻薄的, 腐蚀剂
idioms:
中文(繁體)(Chinese (Traditional))
adj. - 腐蝕性的, 刻薄的
n. - 腐蝕劑
idioms:
한국어 (Korean)
adj. - 부식성의, 통렬한
n. - 부식제, 빈정대는 말
日本語 (Japanese)
adj. - 痛烈な, 腐食性の, 焼灼性の, 火線の, 辛辣な, 皮肉な
n. - 火線, 腐食薬
idioms:
العربيه (Arabic)
(صفه) كاو, لاذع, محرق
עברית (Hebrew)
adj. - מאכל, שורף, חריף, צורב
n. - חומר מאכל
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