Eclipsed conformation refers to a specific arrangement of atoms in a molecule, particularly in alkanes, where the substituents on adjacent carbon atoms are aligned with each other. This alignment creates steric strain, as the electron clouds of the substituents repel each other, making this conformation less stable compared to others. In contrast to the staggered conformation, where substituents are positioned at an angle to minimize repulsion, the eclipsed conformation is higher in energy. This concept is important in understanding molecular stability and reactivity in organic chemistry, especially in the study of cycloalkanes and conformational isomerism.