I am writing a book on Drumming. The word "Beat" is confusing for many Musicians and you can see why it is difficult for Drummers: there are beats in a bar, a drum beat and we beat the drum, so do they mean the same thing? The answer is yes.
A beat is a repeated pattern and we know where it starts. Beating a Drum is repeated and we know where is started, a Drum Beat is repeated and we know where is starts and the beats in a bar mean the repetitions in music that we can understand, because we know where they start.
When you get to the top levels of Music, you see similarities between Music and the Written Word. Both have Sentences, both have Paragraphs and both have Cadences. Both also use beats. In Poetry the rhythm is described in terms of beats. "The cat sat on the mat" The beats are in bold. Single syllable words are the clearest for showing the beat.
As a Music Teacher, I say, "There are no tricks, there are no traps, there is just Teaching". I ask, "How long is a beat?" The answer is four letters: it's not a trick question.