IPA: /ˌdɪsɪˈmɪl.ə.ti/
KK: /dɪsɪmɪlɛrɪti/
The quality or state of being different or not the same as something else.
There is a noticeable dissimilarity between the two paintings.
Dissimilarity → It is formed from "dis-" (meaning apart or not) and "similaris" (from Latin, meaning similar). The word describes a state of being not similar or having differences.
Think of 'not' or 'apart' ('dis-') when you consider things that are 'similar' — that's how you remember that 'dissimilarity' means a lack of similarity.