sign, sine, syne

Sign or sign means a notice, announcement, identification, or advertisement for public view, in words or symbols--
Watch for the stop sign.
The sign said the store is open until 9.
The sign says "trees for sale".
We missed the sign for our exit.
Sign may also mean a gesture--
He made a sign that he wanted to leave.

Sine or sine ( rhymes with sign ) is a term used in trigonometry--
A sine is one of the relationships between the parts of a triangle.
Find the sine, cosine and tangent.

Now that you know that, you can say--
"The surveyors used the sine of the measurements to determine where the sign should be installed."

Note--"syne" ( rhymes with "sign", but with a "z" sound ), as used in the expression "auld lang syne", is a Scotch word. The phrase means "for old time's sake".  The people of Scotland speak English, but still use many words from their original language--
They always sing "Auld Lang Syne" at New Year's parties.

Note #2--"cosign" or "co-sign" means to sign the papers for someone who is getting a loan from the bank. Parents might cosign a car loan for a young person, for example. If the young person cannot make the loan payments, the parents have agreed to pay by cosigning the loan--
His dad agreed to cosign his car loan.
Not to be confused with "cosine", another trigonometry term--
Find the sine, cosine and tangent.

Note #3--"zine" ( rhymes with teen ) means a small circulation magazine, either digital or on paper--
He started a zine on the internet, and has a lot of subscribers.

Note # 4--"sine" is a Latin word meaning "without", still used in the phrase "sine qua non", meaning the necessary thing. If the necessary thing or idea is missing, the whole thing described by the phrase does not exist--
 Baggy clothes are the sine qua non of hipness, to some young people.