polttopiste

Etymology

poltto (“burn, burning”) +‎ piste (“point”), from the fact that a convex lens concentrates the rays of the sun into the focus of the lens, which may cause a flammable material to catch fire.

Pronunciation

• IPA^(key): /ˈpoltːoˌpisteˣ/, [ˈpo̞l̪t̪ːo̞ˌpis̠te̞(ʔ)]
• Rhymes: -iste
• Hyphenation^(key): poltto‧piste

Noun

polttopiste

1. (optics) focus (point at which reflected or refracted rays of light converge)

   Synonym: fokus

2. (mathematics) focus (point of a conic at which rays reflected from a curve or surface converge)

Further reading

• “polttopiste”, in Kielitoimiston sanakirja [Dictionary of Contemporary Finnish]‎ (in Finnish) (online dictionary, continuously updated), Kotimaisten kielten keskuksen verkkojulkaisuja 35, Helsinki: Kotimaisten kielten tutkimuskeskus (Institute for the Languages of Finland), 2004–, retrieved 2023-07-03