Disk partition interrupted So I was partitioning my macbook's hard disk so as to install addition operating system. 

But as disk utility was in the process of partitioning, I closed the disk partition (for a reason) thinking it wont save the changes and I will start again. 

Big mistake. 

All the free space (a lot) I had before is now showing as "other" and the disk isn't partitioned. How do I fix this? Thanks!
If the formerly-free space is showing up as 'other', the implication is that your current system partition is perfectly OK?

I would recommend to start with, booting from the Recovery partition, and doing a 'Verify Disk' and/or 'Repair Disk' on the system partition.

Is the 'other' space actually a partition, or is it free unpartitioned space on the drive?

If it's a partition, you can use Disk Utility to select that partition and use 'Erase' it in the format you wanted - give it the name you want at the same time.

If not, you can just create the new partition in that space.