相当 (xiāng dāng) as an adverb means 'quite, fairly' — it's a moderate degree, stronger than 比较 (bǐ jiào 'relatively') but less intense than 颇 (pō 'quite, considerably'). As a verb it means 'to be equivalent to', similar to 等于 (děng yú) but often used for abstract matching (e.g., ability, status) rather than exact mathematical equality.