what does bk and blk mean

[km51]

I am searching sites to rent an apartment and I see 'bk' and 'blk' mentioned with regard to the address. I have yahood, googled, expated etc and cannot find what this means. Any help would be appreciated.
Also, with regard to condominiums, is it better to be high up, middle or ground ? Have no family so not bothered about small children falling over the balcony
cheers
2009 singapore expat

[jpatokal]

"Block". Usually refers to HDB apartments.

[km51]

but of course !
duh ...
cheers