Biosensor is a device to detect biological activity or function. Optical sensor is a light assisted measurement of a phenomenon. Morphogenesis is the process by which tissues develop into their final, functional shape. Mechanobiology is defined as the study of the mechanisms by which cells detect and respond to mechanical stimuli. Mechanotransduction is defined as the mechanism through which cells sense, integrate, and convert mechanical stimuli into biochemical signals. Mechanosensing refers to the ability of cells to perceive the mechanical signatures of their environment. Mechanogenetics refers to the convergence of mechanobiology and synthetic biology, to design innovative strategies for harnessing mechanical signal transduction pathways to control gene expression. Elasticity is the ability of a material to resume its normal shape after being stretched or compressed. Stiffness refers to a resistance to deformation. Viscoelasticity is the rate dependence of the resistance of the tissue to an applied force. Stress relaxation is a time-dependent decrease in stress under constant strain. Strain hardening is the strengthening of a material by plastic deformation. Organoids are 3D organ-like structures derived from stem cells. Spheroids are spherical solid structures often used to model tumors. Scaffolds are extracellular matrices (natural or synthetic hydrogels) that support the growth of cell is 3D. Durotaxis refers to the directed migration of cells towards an ECM stiffness gradient. Chemotaxis refers to the directed migration of cells towards an increasing chemical gradient. Extracellular matrix (ECM) is a combination of proteins and molecules that support, and give structure to, cells and tissues in the body. Matrisome is the list of all proteins that constitute the extracellular matrix. Solid stresses emerge in a tissue from the structural components related to growth, and represent the sum of the physical forces exerted during growth.