1) Coincidental 2) Coinciding 3) Concurrent 4) Cooccurring 5) Exactly corresponding 6) French word used in English 7) Happening at the same time 8) Matching point for point 9) Simultaneous 10) Synchronal 11) Synchronic 12) Synchronous 1) Coincidental 2) Coinciding 3) Concurrent 4) Simultaneous 5) Synchronal 6) Synchronic 7) Synchronous 
In geometry, two vectors can be said to be coincident when they point in the same direction, regardless of their magnitudes. In other words, they lie upon each other. If two coincident vectors are both normalized (shortened or lengthened to be one unit long), the resulting vectors would be identical. The dot product of two coincident vectors is th...
• (n.) One of two or more coincident events; a coincidence. • (a.) Having coincidence; occupying the same place; contemporaneous; concurrent; -- followed by with.
Co·in'ci·dent (ko*ĭn'sĭ*d e nt) adjective [ Confer French coïncident .] Having coincidence; occupying the same place; contemporaneous; concurrent; -- followed by with . « Christianity teaches nothing but what is perfectly suitable to, and coincident wit...Co·in'ci·dent noun One of two or more coincident events; a coincidence. [ R.] ' Coincidents and accidents.' Froude. 
[adj] - occurring or operating at the same time 2. [adj] - matching point for point
coincidental adjective occurring or operating at the same time; `a series of coincident events`
happening at the same time. · coinciding; occupying the same place or position. · exactly corresponding. · in exact agreement (usually fol. by with).