Subdiffusion (α<1) arises in continuous-time random walks (CTRW) where waiting times between steps follow a power-law distribution ψ(t)~t-(1+α). Unlike normal Brownian motion (α=1), subdiffusing particles get trapped for long times — relevant to diffusion in crowded cells, porous media, and anomalous transport in glasses. The MSD log-log plot reveals the anomalous exponent.