Could anyone help me with a word please?

mağazalarda -

mağazar i think means large business or shop
and I thought lar was plural but what does the da mean?

Maybe it means none of this but I would like to know the meaning please?

If anyone can help I would be grateful

mağazalarda : in stores

-da, -de is locative case suffix and means "in, at or on".

example:
İstanbul'da : in İstanbul
Türkiye'de : in Turkia
okulda : at school

thanks so much for your quick reply. I will always remember that now!!