Here's what dictionary.com says:
held in deep affection; cherished: loved companions; much-loved friends.
1. greatly loved; dear to the heart.
2. a person who is greatly loved.
He writes long letters to his beloved.
'Beloved' is used as both an adjective ('strongly or dearly loved') and a noun ('that which is loved').
As an adjective: I cried for a week when my beloved German Shepherd passed away.
As a noun: John took his beloved on a cruise to celebrate their honeymoon.
held in deep affection; cherished
a beloved friend, object, etc. is one that you love very much. This word is sometimes used humorously to say that someone likes something too much
someone that you love and who you have a romantic relationship with
loved is an adjective. Which pair of shoes do you want to wear? the loved ones.
beloved is a noun - the object of my affections. YOU are my beloved.
Other than that, it's mostly semantics.