• Study of abiosis
• Study of acarology
• Study of acoustics
• Study of acoustoclasticity
• Study of acoustoelasticity
• Study of aerodynamics
• Study of aerohydrodynamics
• Study of aerohydroelasticity
• Study of aerohydromechanics
• Study of aerology
• Study of aerophysics
• Study of aerostatics
• Study of aerotechnics
• Study of aerothermoelasticity
• Study of agroclimatology
• Study of agrology
• Study of alchymy
• Study of allomerism
• Study of anamorphism
• Study of angelology