Variations include: Hun-no, Xiung-Nu, Hsiong-Nu, Hsiung-Nu, Hiung-No.
The "奴" tribes and affected statelets included:
An entry in a Chinese dictionary says Xiongnu (Xiong1nu2), (匈奴) n., The Huns, Mongolian tribes in northeastern China and Mongolia, historically under various names (玁狁 xian3 yun3, 匈奴 xiong1 nu2, and 胡 hu2) 1000 B.C. to 6th cen. A.D. In the 4th, 5th and 6th centuries, five northern tribes, including Tartars, Mongols, Turkicss invaded and occupied North China. These tribes are categorically labelled hu2 di2 (胡狄), such period is referred to as "Five barbarian tribes' invasion of China" (五胡亂華) by Chinese historians. By the 6th century, the term hu2 simply means the barbarian invaders including more than the Huns). Sentences in parentheses are highly disputable.
In fact, the 匈 must not be confused with their 奴. The first reference to the 'Savage' ones in Chinese records is when Chunwei (chinese characters are missing) the son of the last Xia (夏) emperor Jie returned with 500 members of his 夏 nation to his relatives the 匈 after his father was removed because of his decadent ways.
The Chinese historians' definition of "Five barbarian tribes' invasion of China" (五胡亂華) never included Tartars, Mongols and Turkics. Hu (胡,Hu2) was a collective noun for non-Chinese tribes in China. The word Tungus derives from Tong (eastern) Hu (barbarian?). Di (狄,di2) specified to those lively in Northern China, as in the famous term: Rong Yi Man Di (戎夷蠻狄(?), rong2 yi2 man2 di2) which depicted all non-Chinese tribes living around China. Note that all four characters rong2 yi2 man2 di2 were all collective nouns for non-Chinese tribes. They are not names of individual tribes.
The term "Mongols (and hence its adjective Mongolian)" was abused mostly by western historians since the ravage of Europe in 13th century by Mongols led by grandson of Genghis Khan was so destructive. Any group of herdsmen that had resided on modern Mongolian steppes were referrred as Mongolian, regardless to when they appeared in history. This broad terminology is certainly misleading.
Similarly, in the past some Chinese historians have depicted "Hu" as the equivalence of "Xiongnu" or Huns. For examply the Xiongnu/Huns had already ceased top exist by the time of Mulan. It would have been Turks that she had to deal with. This terminology is outdated and no longer used by current researchers. As noted above, "Hu" is a collective noun. This should be kept in mind when one comes across any old or traditional Chinese historical text.