dys ‧ lex ‧ i ‧ a /dɪsˈleksiə/ BrE AmE noun [uncountable]
[ Date: 1800-1900 ; Origin: dys- 'bad' (from Greek ) + Greek lexis 'word, speech' ]
a condition that makes it difficult for someone to read and spell
—dyslexic adjective :
Two of the children in the class are dyslexic.