"The Eagle: A Fragment" is written in two stanzas of three lines each and utilizes the iambic-tetrameter form of meter. Iambic meter is structured in units of two syllables where the first syllable is unstressed and the second is stressed. If the stresses are identified, the first line appears as follows:
Heclasps / thecrag / withcrook / edhands;
"Tetrameter" ("tetra" meaning four) indicates that there are four iambic units, or feet, in each line. It should be noted, however, that Tennyson varies the iambic pattern in two places. In both lines 2 and 3, the first two syllables do not form an iamb (an unstressed syllable followed by a stressed syllable), but rather a trochee, meaning that the first syllable is stressed and.....