To gather for oneself, as for one's pleasure or profit: amassed a fortune. See Synonyms at gather.
To accumulate or assemble a large quantity of: "The astronomers had amassed compelling evidence that the galaxies indeed were speeding away from the earth and from each other” ( George Johnson).
To come together; collect.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.