five notes of pentatonic scale, roughly do, re, mi, sol, la; five classes of initial consonants of Chinese phonetics, namely: 喉音[hóu​yīn], 牙音[yá​yīn], 舌音[shé​yīn], 齒音|齿音[chǐ​yīn], 唇音[chún​yīn]