spongin

is likely misspelled.

has no English definition.

As a noun spongin

is a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponges proteinaceous compounds of which the spicules in Demospongiae are composed.

As nouns the difference between spicule and spongin

is that spicule is a sharp, needle-like piece while spongin is a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponges proteinaceous compounds of which the spicules in Demospongiae are composed.

As nouns the difference between spondin and spongin

is that spondin is (protein) any of a group of proteins that are involved in axon guidance while spongin is a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponges proteinaceous compounds of which the spicules in demospongiae are composed.

As nouns the difference between spongin and sponging

is that spongin is a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponges proteinaceous compounds of which the spicules in demospongiae are composed while sponging is the application of a sponge.

As a verb sponging is

.

As nouns the difference between spongin and spongoblast

is that spongin is a horny, sulfur-containing protein related to keratin that forms the skeletal structure of certain classes of sponges proteinaceous compounds of which the spicules in demospongiae are composed while spongoblast is (zoology) in sponges, one of the cells that secrete spongin.