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[Fr. base, L. basis, fr Gr. basis, step, pedestal]

1. The lower or supporting part of anything. ANT: apex.
2. The principal substance in a mixture.
3. Any substance that combines with hydrogen ions (protons) or accepts hydrogen ions, e.g., a Bronsted base. Strong bases, e.g., sodium hydroxide or lye, are corrosive to human tissues. Whether an unknown chemical compound is a base or an acid may be determined by the color produced when it is added to a solution containing an indicator or by measurement of pH by an electrometer and suitable pH electrode.
SYN: SEE: alkali
SEE: acid; SEE: pH
4. A substance that can donate a pair of electrons; a Lewis base.
SEE: Lewis base
5. Vehicle (1).

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