A specimen is a single example of something, chosen to show what the whole group is like. When a scientist collects a specimen of a butterfly, she's choosing one individual butterfly to study and learn from. That one butterfly represents its entire species: by examining it closely, she can understand what butterflies of that type look like and how they're built.

Museums display specimens of minerals, fossils, and animals so visitors can see real examples up close. A doctor might ask for a blood specimen to test for illness: one small sample that reveals information about your whole body. Botanists press plant specimens between pages to preserve them, creating a permanent record of what that plant looked like.

The word can also describe an impressive or unusual example of something. You might hear someone call a particularly large fish “quite a specimen” or joke about someone strange being “a real specimen of humanity.” In this sense, specimen suggests something worth examining because it's remarkable in some way.

Notice that a specimen stands in for a larger group. One leaf specimen in a biology textbook teaches students what leaves of that tree species look like. The specimen is the ambassador, the representative, the single example that helps us understand the many.