focal definition by Wordo

Adjective

Belonging

to

,

concerning

,

or

located

at

a

focus

.

Noun

One

of

two

lines

perpendicular

to

the

axis

of

a

cone

such

that

the

cosine

of

the

angle

between

the

line

and

the

axis

is

equal

to

the

ratio

of

the

cosines

o

the

semiangles

of

the

cone

.