parallel

(adj) Running side by side, never meeting; existing or happening at the same time. (noun) A comparison of similar things; a line of latitude.

• parallelism/ˈpærəlɛlɪzəm/(n)平行；对称
• unparalleled/ʌnˈpærəlɛld/(adj)无与伦比的

• draw a parallel
• run parallel
• a parallel process
• parallel development
• parallel structure
• in parallel
• unparalleled success

1. 1.The two teams were running parallel investigations without knowing the other existed.
2. 2.There are clear parallels between what happened in 2008 and what we're seeing in markets today.

• comparable/ˈkɒmpərəbəl/— similar; able to be compared
• analogous/əˈnæləɡəs/— similar in certain respects
• simultaneous/ˌsɪməlˈteɪnɪəs/— happening at the same time

from Greek "parallelos" = beside one another, from "para-" (beside) + "allelon" (of one another)