用法:
1 in or forming a straight line 直线的; 形成直线的:
rectilinear motion 直线运动.

用法:
2 bounded by or having straight lines 用直线围著的; 有直线的:
a rectilinear figure 直线图形.

• uproot
• upset
• upshot
• upside-down
• upstage 1
• upstairs 1
• upstanding
• upstart
• upstream
• upsurge
• upswing
• uptake
• uptight
• up-to-date
• up-to-the-minute
• uptown
• upturn
• upturned
• upward
• upward (also upwards / -wEdz; -wLdz/)
• upward mobility
• upwards of
• upwind
• uranium
• urban