In Portuguese, we always use "no singular/plural" when talking about grammar number (eg um verbo/adjetivo no singular/plural").

I have noticed that "en singular" (without an article) is more usual than "en el singular" in Spanish (and Google confirms it). Is there any difference in meaning between both?

Is the same pattern used when talking about a verb conjugation? Is "primera persona de singular" more usual than "primera persona del singular"  ?

In Portuguese, we always use "no singular/plural" when talking about grammar number (e.g., "um verbo/adjetivo no singular/plural").

I have noticed that "en singular" (without an article) is more usual than "en el singular" in Spanish (and Google confirms it). Is there any difference in meaning between both?

Is the same pattern used when talking about a verb conjugation? Is "primera persona de singular" more usual than "primera persona del singular"?