[jerf]

Taking your question seriously, yes. Two major schools of thought are "prescriptive" vs. "descriptive". This terms are usually applied to the noun "grammar" but it works for vocabulary, too. See: http://amyrey.web.unc.edu/classes/ling-101-online/tutorials/...

Descriptively, breakfast is clearly an early-morning meal eaten within an hour or two of the end of sleep. There is also, at least in America where I can speak for it, a set of associated "breakfast foods", making it reasonable to "have breakfast for dinner" and most people know what you mean. (i.e., even my 5-year-old knew precisely what that meant when I first said it, so one should carefully consider one's internet-pedant options before claiming that makes no sense :) ) Prescriptively one could make a case for "the meal that breaks your fast", though I daresay it would be a rather weak case. The term "fast" is almost dead in modern American English, though it may be making a comeback via things like Intermittent Fasting: https://www.nerdfitness.com/blog/2013/08/06/a-beginners-guid... (Which, for the purposes of this post, I'm merely pointing out a word usage. Though I do it myself now, I'm not defending or advocating it here.)