connascence

from The Century Dictionary.

• noun The birth of two or more at the same time; production of two or more together.
• noun The act of growing together or at the same time.

from the GNU version of the Collaborative International Dictionary of English.

• noun The common birth of two or more at the same tome; production of two or more together.
• noun That which is born or produced with another.
• noun obsolete The act of growing together.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The birth of two or more things at the same time.
• noun The act of growing together.
• noun computing A relationship between two or more elements of software in which changing one necessitates changing the others in order to maintain overall correctness.
• noun obsolete That which is born or produced with another.
• noun obsolete The act of growing together.