リトマス紙しリトマスしMeanings1nounlitmus paperA type of pH indicator paper. Often used in chemistry contexts. The full term リトマス試験紙 is also common.See also: リトマス試験紙リトマス紙しを使つかって水すい溶よう液えきの酸さん性せい・アルカリ性せいを調しらべた。We tested the acidity or alkalinity of the aqueous solution using litmus paper.