のみならず

のみならず means "not only… but also": what is true of the first item is true of more besides. It follows a noun directly, or a verb or い-adjective in the plain form; a な-adjective takes である first.

• × 便利のみならず → 便利であるのみならず

The second half usually carries も. When the addition is a surprise, it takes まで or さえ instead.

のみならず, ばかりでなく or だけでなく

All three mean the same and differ in register. だけでなく, or だけじゃなく, is the one you say. ばかりでなく is more formal, and のみならず is the most formal – news, essays, speeches. In conversation のみならず sounds stiff.

Opening a sentence

のみならず can also stand at the start of a sentence, where it means "what is more" and adds a second point to the one before. This is written usage. In speech you say それに or しかも.