Originally Posted by sundog
Is there a legal definition for 'age of majority'?
Forgive me for forgetting about your question.
Yes, there are definitions. The age at which a person, formerly a minor or an infant, is recognized by law to be an adult, capable of managing his or her own affairs and responsible for any legal obligations created by his or her actions.
The common law age of majority was 21. Before this (medieval times), the age was 25. However, each State has the ability to set the age at whatever arbitrary age it wants. "If a legislative body wishes, for whatever purpose, it can wave a magic wand and emancipate (a minor) to suit its convenience. Though 21 usually is the dividing line between minority and majority, the age of majority in Michigan (in 1972) is now 18. The state seemingly can be as arbitrary as it pleases in raising or lowering the barrier for all or just some purposes." Smith v Smith (1972) 433 Mich. 606 (as an example of what the courts have said).
As a federal construct, the age is now 18. The same goes for the State of Texas (and many other States).