Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
allĭgāmentum (adl-), i, n. [alligo], = alligatura: pisces habent inter se adligamentum luteum continens usque ad priores pedes, Schol. ad Germ. Arat. 240; v. Hygin. Astronom. 3, 29.