Hi Ankita,
The word halogen is also derived from Greek word halo meaning salt and gen meaning producing. The group 17 elements of the modern periodic table (i.e., F, Cl, Br, I and At) are called halogens. This is because they form salts namely fluorides, chlorides, bromides and iodides, many of which occur in sea water.
Hope, this answers your question.
Cheers!