High-energy-density matter (HEDM) is a class of energetic materials, particularly fuel, with a high ratio of potential chemical energy output to density, usually termed "thrust-to-weight ratio", hence "high energy density".
High-energy-density matter encompasses a category of highly energetic substances, particularly fuels, distinguished by their exceptionally high potential for energy release relative to their mass, often denoted as "thrust-to-weight ratio" and thus termed "high energy density".