1)А lot of one-syllable masculine nouns end with "a".
глаз-глаза, дом-дома, луг-луга, сорт-сорта, лес-леса, цвет(color)-цвета
2)If a masculine singular noun has two or more syllables and the first syllable is stressed, they also end with "a".
Адрес-адреса, гОлос-голоса, дОктор-доктора, вЕчер-вечера
3.There are some other words like профессора, директора, рукава, инспектора. There's no rule here.You'd better memorize them.