What is an Infant?

An 1830 document indicates your ancestor is an infant and has a guardian appointed for him. The next year the ancestor marries. What gives?

What gives is that an "infant" in the legal sense is someone who is under the age of majority. While that can vary from state to state and has changed over time, it typically is 18 for females and 21 for males.

So your ancestor could be 15 years old and be an infant.

Just something to keep in mind.