Rudiment

Knowing how to operate a computer is a rudiment of digital literacy.

Understanding the principles of flight is a rudiment of aviation.

The early telephones were a rudiment version of today's smartphones.

The early computer programs had a rudiment user interface.

The basic mathematical equations were rudiment compared to the complex ones used in modern science.

The basic drum set was a rudiment instrument in comparison to the complex ones used by professional musicians.

The primitive houses made of mud and straw were a rudiment form of shelter.

The cavemen used rudiment tools made of rocks.

The dewclaw on a dog's paw is considered a rudiment structure.

The gills in adult amphibians are considered rudiment organs.

The nictitating membrane in some animals is considered a rudiment structure.

The hind legs of a snake are considered rudiment organs.