Plural of aligner; multiple tools, devices, or people that align or arrange things into proper position.
From 'aligner' + '-s' (English plural marker). The plural maintains the '-er' agent/instrument noun form while marking multiple instances.
Invisible braces called aligners are why 'aligner' became a household word in the 2000s—a product name basically renamed a technology and proved that clear plastic teeth-straighteners were viable.
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