What do the [+'s] mean in sda1 & sda7, sdb2 & sdb5 below?

[Steven Vollom]

If you did not understand the below, what would you Google or what in 
man:locate would direct me to an answer to my question?  Thanks!

*Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x47a447a3

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        1824    14651248+  83  Linux
/dev/sda2            1825       24792   184490460    f  W95 Ext'd (LBA)
/dev/sda5           16523       24792    66428775   83  Linux
/dev/sda6            1825        2006     1461852   82  Linux swap / Solaris
/dev/sda7            2007       16522   116599738+  83  Linux

Partition table entries are not in disk order

Disk /dev/sdb: 81.9 GB, 81964302336 bytes
255 heads, 63 sectors/track, 9964 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xffffffff

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2591    20812176   83  Linux
/dev/sdb2            2592        2856     2128612+  82  Linux swap / Solaris
/dev/sdb3            2857        9964    57095010    5  Extended
/dev/sdb5            2857        9964    57094978+  83  Linux
steven at Studio25:~$                                 *

Steven