How about both of them actually being words?
One of them is always an apparently random sequence of characters.
I want my users to be able to engage with the sites I manage, therefore I have ditched captcha/recaptcha and opted for an alternative more user-friendly solution.
As far as anti-spam solutions go, captcha/recaptcha must belong at number 1 in the user interface hall of shame.
Have any of you heard of 'user experience'?