A trait is a characteristic shown by an organism.
For example a Tt plant would show the 'tallness' trait.
It seems to me that, by analogy, sickle cell anaemia (SCA) carriers should show the 'normal' trait, but I have found on various sites that SCA carriers are described as having the sickle cell trait because as carriers they can pass the mutated gene to their children.
This doesn't make sense to me, as showing a trait and passing it to the next generation are two different things. We do not say a Tt plant has the dwarfness trait just because it can pass it to the next generation.
So what is the exact definition of the term 'trait'?