Translation:the loaf of bread
So, masculine nouns are made definite with the addition of -ul, and feminine nouns are made definite with either the addition or replacement of the final vowel with -a?
On the topic, do all masculine nouns end in a consonant and all feminine nouns end in a vowel? (Judging from the completely arbitrary genders in French, that's probably a long shot, but a guy can dream!)
You're right that it sounds like there is a glide in the word, but it isn't used from the letter y. It may be similar to the ñ like in spanish, but it actually uses the "ə" which produces an "uh" sound like in "the". So, try thinking of the word like "p-uh-y-nya" when pronouncing it.
Romanian pronunciation is simple. The golden rule is: 1 letter -> 1 sound. Very few exceptions. There are no missing sounds or letters that are not read. The word "pâinea" has 2 syllables: pâi - nea, first one accented. A , ă and â (î) are always long vowels (we call them full vowels). Naturally, "i" and "e" here are semivowels (or glides, as you call them) because there can not exist 2 full vowels in the same syllable.