The word "strook" refers to a line or stroke. Its spelling may seem unusual, but it can be explained using the International Phonetic Alphabet (IPA) transcription. In IPA, the vowel sound in "strook" is represented by the symbol /ʊ/. This sound is commonly spelled with the letters "oo" in English. Additionally, the "k" at the end of the word represents a voiceless velar plosive sound, which is often spelled with the letter "k". Thus, the spelling of the word "strook" follows rules of English phonetics and phonology.