Different letter forms

[ShubhamSanklecha]

What is the difference between the alphabet 'a' with the open aperture and a normal alphabet 'a' with the closed counter?

And what they called? Any specific name?

[Ralf Herrmann]

It’s a stylistic choice with different roots in the history of writing. 

The first one is called “two-storey a”, the second is a “one-storey a”. 

[Riccardo Sartori]

You can find those, along with many others, in this very site’s Typography Terms – Glossary and Dictionary.

The single-storey |a| is modeled after the common cursive form, and is used in italics, in numerous geometric sans typefaces, and in so-called “infant” designs.

[bellefont]

Quick question- Is the "two-storey" the same as double story?

[Riccardo Sartori]

32 minutes ago, bellefont said:

Is the "two-storey" the same as double story?

Yes, of course, as well as “one-storey" is the same as “single-storey”.