I was trying to find the meaning of the word "Leader" in Greek. I went
thro a website http://www.perseus.tufts.edu/cgi-bin/enggreek?lang=greek
This web site gave me lots of words including a word "Semantor". I
need to know the correct meaning of the word "semantor" in Greek and
English.I checked up with someone who said the following -
"Well, the thing is that sêmantôr or (shma/ntwr) is by no means a
Greek word. Semantor in English is a palaeontological name to identify
an aquatic carnivore from the lower Pliocene, which was once
considered to belong to a separate pinniped family but is now
considered a mustelid. I don't see how this could mean "leader"".
Please check the above mentioned website and let me know what is the
correct meaning of the word"sêmantôr".Why does the persues project by
tufts univeristy at http://www.perseus.tufts.edu/cgi-bin/enggreek?lang=greek&lookup=leader&type=begin&options=Sort+Results+Alphabetically
shows the of meaning leader as semantor. Please let me know the
meaning in greek and english.

Dear samin,

I have searched the site using as many internal cross-references and
derivations of "sêmantôr" and its elements as possible. Now I can
assure you that "sêmantôr" is an actual expression from ancient Greek,
meaning "one who gives a signal, a leader, commander", but also
someone riding a horse, commanding soldiers or a guide and even a
herdsman.

The etymology behind it is as follows:
"sêmainô" means as much as "to shew by a sign, indicate, make known,
point out". This makes a sêmantôr someone who leads others by giving
them directives.

The term "sêmantôr" is indeed proper Greek. It can be found in Homer's
"Iliad": "(...)sigêi deidiotes sêmantoras(...)"; and in Homer's
"Odyssee": "(...)ou toioi sêmantores eis' eni oikôi(...)", both times
referring to military commanders.
It was also Homer in his "Iliad" who used the term for a horserider:
"(...)hippô deuesthên sêmantoros(...)".
Also, Herodotus used the word to identify a leader of subordinate
military officers in his "Histories": "(...)êsan alloi sêmantores."
Please keep in mind that all these forms of the substantive "sêmantôr"
are inflected, thus the varying suffixes.

All meanings of "sêmantôr" given by the Perseus Project dictionary are
based upon ancient works of Greek literature. Thus the term is
doubtless correct. However, it might be not in use anymore in modern
Greek, at least not with the meaning of leader. But in case you need a
historic term for "leader", "sêmantôr" will be all right.

Source:
Perseus Project: Greek-English Lexicon
http://www.perseus.tufts.edu/cgi-bin/enggreek?lang=greek&lookup=leader&type=begin&options=Sort+Results+Alphabetically
 (and various other Perseus sub-sites)

Hope this helps!
Best regards,
Scriptor