Polysemy is an English word of Greek origin.  "Poly" means 'many', and "semy" means 'meanings'.  Polysemy is NOT the same a Homonymy.  The word "Homonymy" is a mixture of Latin and Greek.  "Homeo" means 'same' in Latin, and "nym" means 'name' in Greek.

Polyseme is a word with multiple meanings, but all the meanings come from the same etymology.

Homonyms are spelled the same, but have different meanings from totally separate etymologies.

In Dictionaries and Lexicons, all the polysemes are listed under one heading, while the homonyms are listed as separate words.

Line

"Line" has multiple meanings, but they all come from the same etymology.  Therefore, "line" is a polyseme.

1.  Thread, string, cord, rope, etc.

2.  row of something

3.  long, narrow thing

4.  course of conduct

5.  limit

6.  (a) family line (lineage)

    (b) line of fire

    (c) military line

    (d) naval line

    (e) the front lines (combat forces)

    (f) officers of Navy

    (g) things in order

    (h) line of conveyances

    (i) line of musical notes

    (j) (1) production line (line of people working in production) (2) the people responsible for an organization

    (k) sports line up (players)

7.  long, narrow mark on something

etc....