Bismillaahir Rahmaanir Raheem.
Anyone who studies or reads a Hadeeth which contains its chain of narration (Sanad) will always come across the following terms, and therefore it is important to understand what it is used for:
1: Haddathanaa -حدثنا
2: Akhbaranaa – أخبرنا
3: Amba’anaa – أنبأنا
1: Haddathanaa is used when an ‘Aalim narrates a Hadeeth and the student listens.
In certain kitaabs some printing companies shorten this term to just being Thanaa ثنا, but the meaning is exactly the same, it’s just an abbreviated form of the word.
2: Akhbaranaa is used when a student reads a Hadeeth to an ‘Aalim and the ‘Aalim authenticates it.
This is sometimes shortened to look like Anaa انا.
3: Amba’anaa is used when one student hears another student reading a Hadeeth to an ‘Aalim and the ‘Aalim authenticates it.
These are the three terms which have been used by the Muhadditheen in their books, you will also find some ‘Ulamaa using terms other than the ones mentioned here, but they are simply synonyms of these three terms.
Another thing is the usage of a Haa ح in some chains, this Haa is short for Tahweel تحويل, it is used to signify a switch in the Sanad (chain) to a new chain.
This is found alot in the books of Hadeeth like Saheeh Al-Bukhaari etc, where Imaam Bukhaari Rahimahullaah will begin narrating a Hadeeth with one chain, and then switch to another chain from different narrators narrating that same Hadeeth to further strengthen it by it now having two chains of narration.
http://darulilm.wordpress.com/2011/03/25/some-points-regarding-the-chains-of-ahaadeeth/
Some may find this of use also: http://muttaqun.com/hadith.html