placoid

9.9

Having hard flat scales like those on sharks and rays

adjective
/ˈpleɪkɔɪd/

Specialized

: placoide

The shark’s skin is covered in placoid scales that reduce friction as it swims.

Examples

Unlike bony fish, rays have a covering of placoid plates for protection.
Sharks have placoid scales.
Scientists study the unique structure of placoid scales to design better swimsuits.
Unlike bony fish, rays have a covering of placoid plates for protection.
The placoid scales are fascinating!
The shark’s skin is covered in placoid scales that reduce friction as it swims.
Scientists study the unique structure of placoid scales to design better swimsuits.

Synonyms

scaled

vsplacoid

2 4.9

Covered with small overlapping hard plates like fish or armor

is about hard flattened plates rather than general plate coverings

scaley

vsplacoid

1 4.1

Having a body covered with small thin plates like fish or reptiles

is about rigid flattened plates instead of thin overlapping ones

platelike

vsplacoid

1 5.6

Flat and thin in shape like a sheet

is specifically about plates forming body coverings not general shape

Surface Forms

placoid positive

Morphology

placoid = placo (opaque) = placo + oid

The components are specialized combining forms rather than common English words, so learners cannot reliably infer the meaning from the parts.

Etymology

The word placoid comes from the Greek root plak- meaning 'flat' or 'plate' and the ending -oid meaning 'like'. So placoid literally means 'plate-like', which helps you remember scales that are hard, flat plates on sharks and rays.