تراكم
and
ارتكم
It (a thing) was, or became heaped, or piled, up, or together, or accumulated; i. e., collected together, (S, K, TA,) one part upon [or overlying] another. (TA.) You say, تراكم
السَّحَابُ
The clouds were, or became, [heaped, or piled, up,] one above, or upon, [or overlying,] another; as also تراكب. (TA in article ركب.) And تراكم لَحْمُ النَّاقَةِ [lit. The flesh of the she-camel became accumulated]; meaning the she-camel became fat. (TA.) [And تراكمت الظَّلْمَةُ (assumed tropical:) The darkness became condensed, or dense: for the Arabs describe thick darkness as “ darknesses one above another: ” see Qur'an, 24:40.] And تراكمت الأَشْغَالُ and
ارتكمت (tropical:) [Occupations, or the occupations, became accumulated]. (TA.)