[ hah-nee-uh m ]
/ ˈhɑ ni əm /

noun Chemistry, Physics.

a proposed name for dubnium. Symbol: Ha

Origin of hahnium

1965–70; after German chemist O. Hahn; see -ium
Also called unnilpentium, element 105.

Definition for hahnium (2 of 4)

[ yoo-nil-pen-tee-uh m ]
/ ˌyu nɪlˈpɛn ti əm /

noun Chemistry, Physics.

a former name of dubnium. Symbol: Unp

Origin of unnilpentium

1975–80; < Latin ūn(us) one + nīl nothing + Greek pént(e) five + New Latin -ium -ium
Also called element 105. Formerly hahnium.

Definition for hahnium (3 of 4)

[ doob-nee-uh m, duhb- ]
/ ˈdub ni əm, ˈdʌb- /

noun Chemistry, Physics.

a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Db; atomic number: 105.

Origin of dubnium

named after Dubna, the town in Russia where it was first produced; see -ium
Formerly hahnium, unnilpentium, element 105.

Definition for hahnium (4 of 4)

element 105

noun Chemistry, Physics.

Origin of element 105

First recorded in 1975–80
Formerly unnilpentium, hahnium.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for hahnium (1 of 2)

/ (ˈhɑːnɪəm) /


a name once advanced by the American Chemical Society for a transuranic element, artificially produced from californium, atomic no: 105; half-life of most stable isotope, 262 Ha: 40 secondsNow called dubnium

Word Origin for hahnium

C20: named after Otto Hahn

British Dictionary definitions for hahnium (2 of 2)

/ (ˈdʌbnɪəm) /


a synthetic transactinide element produced in minute quantities by bombarding plutonium with high-energy neon ions. Symbol: Du; atomic no 105See hahnium

Word Origin for dubnium

C20: after Dubna, where it was first reported
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for hahnium

[ dōōbnē-əm ]


A synthetic, radioactive element that is produced from californium, americium, or berkelium. Its most long-lived isotopes have mass numbers of 258, 261, 262, and 263 with half-lives of 4.2, 1.8. 34, and 30 seconds, respectively. Atomic number 105. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.