Phenol (C6H5OH) is an aromatic organic compound consisting of a hydroxyl group attached to a benzene ring. It is a white crystalline solid with a sweet tarry odor that becomes liquid above 41°C. Historically used as an antiseptic and disinfectant (carbolic acid), it serves as a key industrial precursor for plastics, resins, pharmaceuticals, and dyes. Phenol exhibits weak acidity (pKa 9.95) and participates in electrophilic aromatic substitution. It is highly soluble in organic solvents but only moderately in water at room temperature. Due to its toxicity and corrosivity, its use in consumer products is restricted. In food chemistry contexts, it appears as a metabolite or contaminant rather than an intentional additive.