I would like to know the difference between a font and a typeface. If anyone could please help me.
I tried to Google it, but I can't understand that in general, Why the term 'Fonts' is used rather than 'TypeFaces'?
I think the best explanation I have found was in this article which explains how fonts constitute a typeface. To quote the article
A typeface is a family of fonts (very often by the same designer). Within a typeface there will be fonts of varying weights or other variations. E.g., light, bold, semi-bold, condensed, italic, etc. Each such variation is a different font. The only evolution in terminology that results from the transition from metal-cast to digital fonts is that (point) size is no longer fixed.
From a historical perspective of how the word font came about, You should check out this excellent article which explains the difference between the two and also talks about the history of the word font. To quote the article
Around the fifteenth century, when printers hand-set type, they had to pull actual metal letters, numbers, and symbols out of a giant box.
This collection of characters was called a “font.”
With regards to typefaces
Typefaces describe the overall look of the characters contained within the font. If you see in Fig. 2, you’ll see a font of News Gothic – News Gothic is the typeface.
Also to quote this article on Nextweb
“the physical embodiment of a collection of letters, numbers, symbols, etc. (whether it’s a case of metal pieces or a computer file) is a font. When referring to the design of the collection (the way it looks) you call it a typeface.”
Lastly these definitions from Adobe can help explain it further
typeface The letters, numbers, and symbols that make up a design of type. A typeface is often part of a type family of coordinated designs. The individual typefaces are named after the family and are also specified with a designation, such as italic, bold or condensed.
One weight, width, and style of a typeface. Before scalable type, there was little distinction between the terms font, face, and family. Font and face still tend to be used interchangeably, although the term face is usually more correct.
A typeface is a distinct design of glyphs, a font is a specific variant therof, consisting of a full set of glyphs.
Helvetica is a typeface, as is Courier. They are different typefaces, and by definition different fonts.
Helvetica condensed bold is a font, as is Helvetica italic. They both belong to the Helvetica typeface, but they are different fonts.
There is a clear distinction:
Helvetica is a type family. Helvetica Bold is a typeface. 12pt Helvetica Bold is a font.
I remember the definition this way: Family > Face > Font
There isn't a clear difference. There is no hard-and-fast definitions of the two.
As other's have pointed out, common usage is that the font is specific to a set of actual letters (be it physical or digital) and typeface is the overall design (that would usually be applied to a number of fonts as a family).
A physical example would be: Futura Bold 12pt lead type.
A digital example would be: Futura-Bold.ttf
But in common usage, was also use 'font' interchangeably with 'typeface'. "Which font are you using? Helvetica?"