前面 and 前边
Are these two synonyms or is there a difference in meaning and usage?
Yes, they are synonyms, so are 后面and后边。But as a native speaker, I would only use 前面and后面。前边and后边are often seen in old text (古白话文) used in novels such as 红楼梦 (Dreams in the red chamber), 西游记 (Journey to the west) etc. That being said, some local dialects may prefer to use 前边and后边，or use them interchangeably in VERBAL conversations.
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Just to add on, in case you are still not sure - technically speaking, 面 means plane，边means corner。Yeah.. they are being used interchangeably with a slight difference in meaning :)
My online dictionary gives side/edge for 边 and side/face for 面 so they seem so similar and slightly different too.
They are alike though 前边 and 后边 are more informal (in google translate, if you type 后边, it will give you a suggestion of 后面). However, there is a slight difference towards what they mean. To simplify it, 前边 means the small place before you (for instance, you could say 球在你前边 (the ball is in front of you)). 前面, however, defines everything that is ahead of you. It’s like ‘ese’ and ‘aquel’ in Spanish. At least, this is what I believe it is. I hope this helped you!
Regarding the distance from the objects on the front side, 前边 and 前面 make no difference to me. Yeah, they are synonyms. I can say both 他在前边排队 and 他在前面排队 for “he is queueing up there”.