decamethylcyclopentasiloxane /dɛkəˌmɛːθɪlˌsaɪkləʊˌpɛntəsɪˈlɒkseɪn/ noun1 •A clear, lightweight liquid used in cosmetics and personal care products. It spreads easily, helps give a smooth, silky feel to skin and hair, and evaporates quickly without leaving much residue.
