UNDERLAY
Meaning of UNDERLAY in English
un ‧ der ‧ lay /ˈʌndəleɪ $ -ər-/ BrE AmE noun [uncountable and countable]
thick material that is put between a ↑ carpet and the floor
Longman Dictionary of Contemporary English.
Longman - Словарь современного английского языка.
2012