Well, as a name it is basically the same, just that the short a is dropped at the end (like it generally is for Hindi words ending in a consonant and no other vowel than short a). As a proper noun the meaning of raj refers to a territory/political domain and could mean kingdom, empire, principality (see the British Raj).

Can someone please explain the name Raj? Is it technically Raja?

I wish the sentences were verbally spokeb out loud when you click on it. Are we really expected to learn all fhe Hindi characters. It's not like many keyboards use the character. I want to learn to speak Hindi not write calligraphy.