The phrase "doth top head" may seem a bit unusual in modern English, but it actually follows some old-fashioned grammar rules. "Doth" is the archaic form of the verb "does" in the present tense, and "top" means "cover" or "surpass". The word "head" needs no explanation, but its pronunciation can vary depending on dialect. Using IPA phonetic transcription, we can spell it as /hɛd/ to represent the "e" sound in the middle. Thus, "doth top head" means something like "exceeds the limit of the mind".