Thrushel is an Old English word that means "thistle". The spelling of the word is based on the pronunciation of the "th" sound, which is pronounced as a voiceless dental fricative, represented by the symbol /θ/ in the International Phonetic Alphabet (IPA). The "sh" sound, which is pronounced as a voiceless palato-alveolar sibilant, is represented by the symbol /ʃ/ in IPA. The combination of these two sounds gives rise to the spelling of the word as "th-r-u-sh-e-l".