Reference
Mechanical engineering glossary
A compact reference for the core terms that appear across the roadmap. Each definition focuses on what the concept means, where it is used and what students commonly confuse.
Glossary terms
Free-body diagram
A diagram of one isolated body showing all external forces and moments acting on it. It is the starting point for equilibrium equations in statics and dynamics.
Course link: Statics
Equilibrium
A state where the resultant force and, for rigid bodies, the resultant moment are zero. In 2D statics: ΣFx=0, ΣFy=0 and ΣM=0.
Common confusion: equilibrium does not mean “no forces”; it means forces balance.
Stress
Internal force intensity inside a material. Normal stress is commonly written as σ = F/A for a uniform axial load.
Course link: Mechanics of Materials
Strain
Relative deformation. Engineering normal strain is often written as ε = ΔL/L, describing change in length divided by original length.
Entropy
A thermodynamic property used to evaluate irreversibility, heat transfer and the direction of real processes. It is central to the second law of thermodynamics.
Course link: Thermodynamics
Reynolds number
A dimensionless ratio comparing inertial and viscous effects in fluid flow. It helps classify flow regimes and judge dynamic similarity.
Re = ρVD/μ
Thermal resistance
A modelling idea that treats heat flow like current through a resistance. It is useful for conduction, convection and combined heat-transfer networks.
Course link: Heat Transfer
Transfer function
A frequency-domain or Laplace-domain representation of how a linear system transforms input into output under zero initial conditions.
Course link: Control Systems
Tolerance
The allowable variation in a dimension or geometric feature. Tolerances connect design intent to manufacturing, inspection and cost.
Course link: Engineering Graphics, Sketching and CAD
Mesh convergence
A numerical verification check in FEA or CFD: refine the mesh and verify that the result approaches a stable value rather than changing arbitrarily.
Course link: Finite Element Methods
Verification and validation
Verification asks whether the model was solved correctly. Validation asks whether the model represents reality well enough for the intended decision.
Factor of safety
A design margin comparing capacity to demand. It accounts for uncertainty in loads, materials, modelling assumptions, manufacturing and use conditions.
FoS = capacity / demand
Next step
Use the glossary with the roadmap.
Look up terms as you study, but let the roadmap decide what to learn next.