The phrase "main carer" refers to the person who is primarily responsible for taking care of someone. They are usually the one who provides the most care, support, and assistance to that person. Full definition
Take time out by sharing your roles as main carers. (rollercoaster.ie)
Why do main carers defending unreasonable access demands not get the same treatment? (attachmentparenting.org)
The scale contains 27 dichotomous items that measure dispositions and attitudes, eg, «maintains attention and concentrates»; social development, eg, «plays alongside others»; and emotional development, eg, «separates from main carer with support.» (pediatrics.aappublications.org)