<![CDATA[Penelitian ini bertujuan untuk meningkatkan penguasaan kosakata siswa kelas sepuluh di SMAN 1 Lewolema melalui pemanfaatan aplikasi Memrise. Pada tahap awal diagnostik, siswa mengalami kendala berulang dalam mengingat kosakata target dan membedakan kelas kata, di mana hanya 17,65% siswa yang mencapai kriteria ketuntasan minimal. Guna mengatasi hambatan instruksional tersebut, rancangan Penelitian Tindakan Kelas (Classroom Action Research) yang mengadaptasi model Kemmis dan McTaggart diterapkan dalam dua siklus tindakan setelah tahap pra-siklus. Subjek penelitian terdiri atas 17 siswa kelas sepuluh yang mengikuti pembelajaran kosakata meliputi nomina, verba, dan adjektiva. Data dihimpun menggunakan tes penguasaan kosakata 30 butir soal objektif, lembar observasi terstruktur, dan catatan lapangan reflektif. Temuan penelitian menunjukkan peningkatan belajar yang berkelanjutan antartahap tindakan, di mana persentase ketuntasan klasikal meningkat dari 17,65% (3 siswa) pada pra-siklus menjadi 52,94% (9 siswa) pada Siklus I, dan mencapai 88,24% (15 siswa) pada Siklus II, disertai kenaikan nilai rata-rata kelas dari 61,18 menjadi 80,88. Bersamaan dengan itu, data observasi mencatat peningkatan keaktifan belajar siswa dari 35,29% pada tahap awal menjadi 82,35% pada Siklus II. Dalam lingkup kontekstual penelitian tindakan satu kelas ini, perpaduan latihan multimedia Memrise, pengulangan berkala (spaced repetition), dan bimbingan guru yang kolaboratif mampu meningkatkan pencapaian kosakata siswa secara nyata. ABSTRACT This study aimed to improve vocabulary mastery among tenth-grade students at SMAN 1 Lewolema through the pedagogical integration of the Memrise application. In the preliminary baseline, students encountered persistent difficulties in retaining target words and grasping word classes, with only 17.65% achieving the institutional passing standard. To resolve this instructional problem, a Classroom Action Research (CAR) design following the Kemmis and McTaggart framework was implemented across two iterative cycles following a diagnostic pre-cycle. The participants comprised 17 tenth-grade students engaged in vocabulary instruction covering nouns, verbs, and adjectives. Data were collected using 30-item objective vocabulary tests, structured classroom observation checklists, and reflective field notes. The empirical findings demonstrated continuous academic improvement across the intervention stages, where the classical mastery percentage increased from 17.65% (3 students) in the pre-cycle to 52.94% (9 students) in Cycle I, and reached 88.24% (15 students) in Cycle II, with the class mean score rising from 61.18 to 80.88. Concurrently, structured observational data documented an increase in active student learning engagement from 35.29% at baseline to 82.35% in Cycle II. Within the contextual boundaries of this single-group action research, the combination of Memrise multimedia drills, spaced repetition routines, and collaborative teacher scaffolding fostered meaningful improvements in students' vocabulary achievement. ]]>
