Qualities or features that make things alike or comparable to each other.
From 'similar' (from Latin similis meaning 'like'). The suffix '-ity' creates an abstract noun meaning 'the state of being similar,' with '-ties' as the plural form.
Our brain is obsessed with finding similarities—it's how we learn, categorize, and make sense of chaos—and the fact that we need an entire word for this concept shows how fundamental comparison is to human thinking.
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