"Granny shoes" is a term used to describe shoes that are old-fashioned and typically worn by older women. It implies that the shoes are not modern or trendy. Full definition
They are a memory foam type shoe, or as my sister says, «old granny shoes.» (theeverydayelevated.com)
This brand does make some very uncute granny shoes (true story, my grandma bought them for me), but they also make a few really classic, pretty boots. (classicingray.com)
Then, as with so many things nowadays, I kept seeing more and more inspirational outfits featuring either these shoes or some other style of block heeled granny shoe.. (shotfromthestreet.com)