Why do we call them lenses instead of objectives?

[goamules]

disregard

[Alan Davenport]

Why do we call them lenses instead of objectives?

Probably for the same reason that most of us refer to fixed focal length lenses as "primes;" it's either:

1) We do not understand the technical terms, and are using them incorrectly.

or

2) Languages change. Word usage and meaning changes over time.

[Emmanuel BIGLER]

I have found reading a US patent for a Zeiss lens in the fifties that
"Photographic objective" is the title
and that the first sentence says :
"the invention concerns photographic objectives for taking or reproduction consisting of six lenses..."

see for example at google patents, Zeiss US Patent for (probably) a Planar lens
Patent number: 2831397
Filing date: Feb 13, 1956
Issue date: Apr 1958

Probably translated somewhere in Germany before submission to the USPTO... however the patent was issued in due form.
But the language used in patents is far from ours, isn't it ? ;-);-)