The Hebrew siach means meditation, musing, complaint, or troubled thought. It describes an ongoing internal dialogue — the mind working through grief, wonder, longing, or praise. From the verb siyach (H7878), it captures the act of speaking to oneself, pondering deeply, or pouring out one's heart in prayer.
Isaac was out in the field meditating (siach) in the evening when Rebekah arrived (Genesis 24:63) — the single reference to his inner life. The Psalms use siach extensively: David pours out his siach before God (Psalm 102:1), meditates on God's works (Psalm 143:5; 145:5), and finds that even his complaint is heard (Psalm 55:17). Job's suffering leads to bitter siach (Job 7:11; 9:27). The theology here is that honest inner dialogue directed toward God is prayer — not just polished words but the raw, unfiltered murmurings of the soul before a God who hears. The lament Psalms validate dark meditation as genuine worship.