Here are some examples of words with the root "proto":
* Prototype: The first or original model of something, often used as a basis for later versions.
* Protostar: A very young star that is still forming from a cloud of gas and dust.
* Proto-Indo-European: The hypothetical ancestor language from which most of the Indo-European languages are descended.
* Protozoa: Single-celled organisms that are considered the most primitive form of animal life.
Essentially, "proto" implies a beginning or origin and is often used to describe something that is the earliest, simplest, or most basic form of its kind.