The meanings are quite similar. The main difference is that start is both a noun and a verb. Begin is only a verb, with beginning as its noun version. Another difference - that start can imply causation. ie - Start a fire. Begin doesn't really suggest this

In most cases, they have exactly the same meaning. In any situation where you can say 'begin' you can also say 'start'. However, the opposite isn't true. You can only use 'start' is expression like 'start the engine'. Start can also combine with other words to make phrases such as 'start up' and 'start out'.

They are very similar, especially as verbs: 'to start', 'to begin'. However, when we talk about machinery we use start rather than begin: 'Start the car' not 'Begin the car'. When we talk about events or processes normally either will work: 'When does the movie begin?' or 'When does the movie start?' As nouns they look different 'the start', 'the beginning'.

btw The word you want is 'difference', not 'deference'.